Federal Investigation Exposes Hidden Network Behind Cooking Oil Thefts Linked to Migrant Group

On paper, it looks like garbage: a murky slurry of fryer grease and crumbs left over from Friday fish fries and late-night wings. But in 2025, used cooking oil is no longer waste—it’s feedstock for the booming biofuels industry. That transformation has turned the back alleys behind New York’s restaurants into the front lines of a quiet, profitable crime wave.

In Western New York alone, Buffalo Biodiesel Inc. (BBD), a regional leader in collecting and recycling used cooking oil, says it has logged over 12,000 thefts and break-ins involving its equipment and oil since 2022. Tanks have been drained overnight. Locks and security seals have been cut. For BBD, this isn’t petty nuisance, but millions of dollars of product disappearing into the shadows.

As it turns out, the disappearances might not be so random.

Court records, federal affidavits, and industry documents show that stolen used cooking oil doesn’t just vanish; it is pumped into unmarked box trucks, pooled in anonymous warehouses, laundered through shell companies, and then sold back into the same biofuel supply chain that is supposed to reward “sustainable” recycling. By the time it reaches a refinery, it can be almost impossible to distinguish from legitimately collected oil.

One case based in the Rochester region exposes the mechanics of this organized theft network. In United States v. Guodeng Chen, et al., federal prosecutors in the Western District of New York charged six defendants with conspiring to steal and sell massive quantities of used cooking oil across state lines. These defendants are alleged to have used commercial trucks, warehouse space in Rochester’s Commerce Drive industrial corridor, and a web of small companies to move the product into interstate commerce. The defendants – Guodeng “Andy” Chen, Didi Huang, Fangfang Yan, Ruimao Yang, Yan Han, and Wen Xiao Zhang – are accused of running part of what investigators describe as an organized theft ring targeting restaurant grease bins across Monroe County and beyond.

The allegations reach far beyond a handful of late-night heists. According to federal filings, investigators seized more than 12,000 gallons of used cooking oil, over $140,000 in cash, and an unregistered 9mm handgun tied to the operation. They traced truck routes, bank transfers, and bills of lading (i.e.: a legal document issued by a carrier to a shipper that serves as a receipt for goods) from Rochester restaurant parking lots to an out-of-state refinery. They even documented a sale of oil to a buyer whose name, investigators were told, began with “D-A-R”—a significant detail as it points to Darling Ingredients, one of the world’s largest players in the rendering and used oil business.

Yet more than two and a half years after the arrests, the case remains unresolved. Federal charges are pending, but state-level prosecution never materialized, not even for the illegal firearm found in a warehouse bedroom.

Behind the scenes, according to sources, federal prosecutors have alluded to receiving pressure to dismiss the charges. The promising lead toward a potential corporate buyer (D-A-R) was never seriously pursued and Monroe County’s then–district attorney, Sandra Doorley, whose office declined to bring state charges in the case, has since been engulfed by her own legal and ethical scandals that ultimately drove her from office.

This article examines what happened in that Rochester grease-theft case from start to finish: how the alleged ring operated, what federal agents say they found, who profited, and why – despite a detailed federal affidavit and a paper trail of oil and money – the case has stalled.

It also places the story in a broader context: a national surge in used-cooking-oil theft and the apparent reluctance of some local prosecutors to aggressively confront organized theft tied to migrant labor and transnational networks.

And at the center of it all is a 40-page document that reads like a roadmap to the underground grease economy, an affidavit sworn by Homeland Security Investigations Special Agent Adam P. Tyrna.

Tyrna describes an organized operation that quietly siphoned thousands of gallons of used cooking oil from Western New York restaurants, moved it through shell companies and warehouses, and pushed it into the global biofuels supply chain.

All six defendants were charged with conspiracy and interstate transportation and sale of stolen goods under 18 U.S.C. §§ 371, 2314 and 2315. The scheme, as laid out by Tyrna, is simple in concept and sophisticated in execution: steal high-value used cooking oil from restaurant tanks in Monroe County, funnel it through warehouses in Rochester, and sell it into interstate commerce as a legitimate commodity.

Why Does Used Cooking Oil Attracts Thieves?

Tyrna’s affidavit starts by explaining the economics. Restaurants typically sign contracts with rendering or recycling companies to collect their used fryer oil. Those companies pay about $0.25 to $0.60 per gallon for used oil and then transport it to refineries where the liquid is cleaned and converted into biodiesel, which can sell for $4 to $5 per gallon. It’s a huge profit margin, which makes the waste product surprisingly lucrative.

Nationally, kitchens in hotels and restaurants generate roughly 3 billion pounds of used cooking oil every year, according to environmental and industry estimates. As biodiesel and renewable diesel have become more attractive, thieves have followed. The National Renderers Association has estimated that tens of millions of dollars’ worth of used grease is stolen annually in the United States.

BBD’s President, Sumit Majumdar, has previously told reporters from other news outlets that grease thefts have cost his company up to $300,000 per week in some regions and about $15 million per year, roughly a third of its revenue.

A Pattern of Nighttime Thefts

By the time federal agents became involved, Monroe County authorities were already seeing a pattern: late-night box trucks, unmarked for any legitimate grease collection company, appearing behind restaurants between about 11pm and 6am.

Tyrna summarized the pattern, stating, “Over the past year, there have been several thefts of used cooking oil from restaurant parking lots within and around Monroe County. These thefts typically take place overnight, when the restaurants are closed and there is little to no foot traffic. Criminals drive trucks to restaurants in the middle of the night and pump the used cooking oil out of their storage tanks.”

In Monroe County and elsewhere, restaurants that contract with used cooking oil collection companies typically have padlocked metal or plastic tanks clearly labeled with the name of the contracted company and fitted with tamper-resistant seals. Under those contracts, once the restaurant pours its waste oil into the tank, legal ownership transfers to the collector, not the restaurant.  That detail matters because from the moment thieves pump the oil out, they’re taking property of the collection company, not “abandoned waste.”

Defendants’ Cover: Rong Cheng Packaging Supply and De Sheng Inc.

The investigation broke open in the early morning hours of April 1st, 2022, when officers in Henrietta, New York, were dispatched to The Distillery restaurant.

Around 4:17am, officers saw a yellow 2007 Ford Econoline box truck coming out from behind the building. The truck bore New York plate 85949NB and was registered not to a grease collector but to Rong Cheng Packaging Supply Inc. at 300 Commerce Drive, Rochester, NY.

The two occupants were later identified as Ruimao Yang and Wen Xiao Zhang. They voluntarily opened the back of the truck. Inside, officers saw two large plastic holding tanks, a “dirty water” pump, and spilled cooking oil on the bumper. There were no placards or company markings indicating authorized UCO transport.

Three days later, on April 4th, officers again stopped the same truck, again with Yang and Zhang inside, this time coming from behind a Dunn Tire in Greece, NY. The men told police they were “looking for cooking oil,” produced a four-page list of restaurants across Monroe and Ontario Counties, and gave officers the address of the house they were renting at 23 Eagan Boulevard in Henrietta.

These encounters led Monroe County investigators to seek court-authorized GPS tracking warrants for the two box trucks (a yellow “Box Truck 1” and a white “Box Truck 2”). Both were originally registered to Rong Cheng and then re-registered to a new entity, De Sheng Inc., with sequential plate numbers 48747NC and 48748NC.

Once the trackers were attached, the pattern became unmistakable. Over a seven-hour overnight period in mid-April, Box Truck 1 made approximately 20 stops at restaurants and plazas around Rochester. When officers retraced the route the next day:

-Nearly every stop featured a grease collection tank.

-Many tanks were empty and missing the security seals or locks that victim companies typically use.

-Most were marked “Victim Company 1,” “Victim Company 2,” or “Victim Company 3.”

Victim Companies Confirm the Oil Was Stolen

Over the following weeks, investigators went to the companies that owned those tanks. Representatives for Victim Company 1, 2 and 3 each signed sworn depositions stating:

-Only their employees are authorized to remove oil from their tanks.

-Tanks always carry tamper-resistant tags.

-Neither Yang, Zhang, or the trucks had any affiliation with their companies.

Where the Stolen Oil Went

Tracking data showed that Box Truck 1 repeatedly returned to a warehouse at 350 Commerce Drive, Rochester, typically in the afternoon, after nights spent hitting restaurant parking lots.

On April 21st, 2022, officers watched the truck parked outside 350 Commerce Drive, pumping oil through a hose into the building for about 67 minutes.

The investigation then widened to the adjacent warehouse at 300 Commerce Drive, the trucks’ registration address. A representative of “Victim Company 3” told investigators that a friend in the trucking business – referred to in the Complaint as Witness 1 – had been contacted to haul oil from 300 Commerce Drive to refineries in Pennsylvania or New Jersey. Witness 1 handed over bills of lading and invoices documenting two April 2022 shipments of roughly 45,000 pounds of used cooking oil each from “Supplier” at 300 Commerce Drive to a refinery in Erie, Pennsylvania.

Later interviews with that refinery and an intermediate “Supplier” confirmed that these April shipments – originating from the Rochester warehouses under the name 2C Wholesale LLC, with a business address of 300 Commerce Drive – had been brokered into the interstate biofuels supply chain.

Bank records showed:

-On April 11th, 2022, 2C Wholesale’s account received a $29,433.60 deposit from the Supplier. Four days later, a $10,000 check was written from that account to Fangfang Yan.

-On April 30th, 2022, the account received another $30,618 deposit from the Supplier. On May 2nd, $7,500 was withdrawn in cash and $3,684 was paid to De Sheng Inc..

According to a later DOJ press release, investigators ultimately traced 95,320 pounds of stolen oil shipped from the Rochester warehouses to the Erie refinery, with the defendants receiving $60,051 in payments for those two loads.

The May 6th, 2022 Raids: Guns, Cash and 12,461 Gallons of Oil

With the pattern established, Monroe County prosecutors obtained five search warrants for:

-The residence at 23 Eagan Boulevard

-The warehouses at 300 and 350 Commerce Drive

-Box Truck 1

-Box Truck 2

On May 6th, 2022, officers watched as Box Truck 1 left 23 Eagan Boulevard and pulled up to 350 Commerce Drive. They noticed the truck now bore the new De Sheng license plate, 48747NC. Moments later, they executed the warrants.

When officers entered 350 Commerce Drive, they recorded three of the defendants actively working with the stolen oil:

Didi Huang, Ruimao Yang, and Yan Han were captured on video unloading oil from Box Truck 1 into large storage tanks inside the warehouse. Huang opened the warehouse door and later told officers that opening the building was his responsibility.

As officers moved in, Guodeng Chen was seen near the collection tanks being filled. According to the affidavit, Chen grabbed cash from a nearby desk and stuffed it into the pockets of co-defendant Fangfang Yan who was in the office area. Officers recovered the money and put it in Yan’s purse, which also contained her identification.

Chen told officers that he leased the warehouse space at both 300 and 350 Commerce Drive, including the portion housing the oil storage tanks.

What investigators seized inside and around 350 Commerce Drive highlighted the operation’s scale:

-9,806 gallons of used cooking oil in tanks inside the warehouse.

-Another 525 gallons in Box Truck 1 parked outside.

-Business and banking records, multiple cell phones and computers.

-Cash on multiple defendants’ persons, including $4,510 in U.S. currency and $710 in Canadian currency in Yan’s purse, $33,130 in U.S. currency on Yan Han, and $1,818 in U.S. currency on Didi Huang.

All told, authorities seized about 12,461 gallons of used cooking oil, which industry representatives at the time valued at more than $73,000.

The searches next door at 300 Commerce Drive uncovered additional incriminatory evidence. At an apparent cover business, workers told officers they were manufacturing and packaging cleaning products for a company called Everclean Eastern Inc.. They said a woman came to the building about every five days and “the big boss” visited once a month.

In an office near the front of the building, officers found an unregistered 9mm handgun stored in a box with a full magazine not inserted into the weapon. Officers also found a backpack containing $107,428 cash in a locked room.

Box Truck 2, parked at 23 Eagan Boulevard, yielded another 500 gallons of used cooking oil, bringing the total seizure to 12,461 gallons.

 “We Don’t Ask Where It Comes From”: Inside the Operation

After her arrest, Fangfang Yan agreed to speak with agents, with the help of a Mandarin interpreter. She waived her Miranda rights and described the business structure she believed she worked for.

According to the affidavit, Yan said she worked for two companies:   Everclean Eastern LLC at 300 Commerce and Geely Box Inc. at 350 Commerce. She said she spent most of her time at 300 Commerce, and that De Sheng was a newly formed company that had only recently started operations.

Yan described Guodeng “Andy” Chen as her boss, someone she saw every day, and said she had been married to co-defendant Didi Huang for about one year at that point. The couple lived with Chen.

Yan’s described the oil collection business to investigators, saying that the large tanks at 350 Commerce stored used cooking oil delivered by the truck drivers. She described Yang and Zhang (the truck operators) as selling oil to “my company.” They would call Huang when they were on their way, pump the oil into the warehouse containers, and Huang would handle storage. When asked where the oil came from, Yan said they deliberately did not ask. She claimed they only purchased oil two or three times and had “not been at the 350 Commerce warehouse long.”

“They just bought the oil and did not ask questions about it,” said Tyrna in his affidavit .

Yan further told investigators that they had already sold one batch of oil. They “prepared the oil and then looked for a client,” ultimately selling it to “a company that begins with the letters D-A-R.”

The complaint does not identify that buyer by name. However, in the used cooking oil industry, one of the largest players is Darling Ingredients Inc., which operates restaurant-services and rendering operations under its DAR PRO Solutions brand. DAR PRO collects used cooking oil from hundreds of thousands of restaurants and ships it to facilities where it is converted into renewable diesel and other products.

One law enforcement source contends that the unnamed “D-A-R” buyer was Darling Ingredients, a direct competitor of BBD, and that the lead was never fully explored by either state or federal investigators. Of note, neither the complaint nor subsequent DOJ press releases name Darling or accuse it of wrongdoing. Darling emphasize that the company invests in anti-theft technology and even runs a “Grease Police” investigative unit to help law enforcement combat grease theft, not facilitate it.

The Federal Case: Interstate Theft and Sale of Stolen Goods

Based on Tyrna’s affidavit, prosecutors charged the six defendants with:

-Conspiracy under 18 U.S.C. § 371 alleging they agreed together to commit federal offenses.

-Transportation of stolen goods in interstate commerce under 18 U.S.C. § 2314, for moving stolen oil worth at least $5,000 across state lines from New York to Pennsylvania knowing it was stolen.

-Sale of stolen goods in interstate commerce under 18 U.S.C. § 2315 for selling stolen oil worth at least $5,000 that had crossed a state boundary.

As in any criminal case, the defendants are presumed innocent unless and until proven guilty. More than two and a half years after the arrests, the federal case remains pending with pre-trial proceedings ongoing. There is no public record yet of a trial verdict.

Missing State Charges and the Monroe County District Attorney

One of the most contentious aspects of this case is what did not happen after the 2022 raids:

Despite the discovery of an unregistered 9mm handgun and more than $107,000 in cash at 300 Commerce Drive, Monroe County did not pursue parallel state charges for firearms or other offenses arising from the search.

According to a source involved with the federal prosecution, an Assistant U.S. Attorney disclosed that the Monroe County District Attorney’s Office – then headed by District Attorney Sandra Doorley – declined to charge the defendants with any state crimes, including gun-related felonies.

Niagara Action further learned that there has been “pressure” on federal prosecutors to resolve or dismiss the case. Why and by whom will be further investigated in another story.

The source who confirmed Doorley’s refusal to bring any state crimes said that the defendants’ status as migrants influenced her decision—alleging an office-level reluctance to prosecute migrant-related crime. The District Attorney’s office has not publicly stated that immigration status played any role in this or any other prosecution and there is no independent documentation that confirms this as a motivating factor.

There is, however, no dispute that Doorley herself has faced significant public scrutiny and formal discipline in recent years, eventually resulting in her stepping down as Monroe County District Attorney.

Doorley’s Own Legal and Ethical Troubles

On April 22nd, 2024, Doorley was clocked driving 20 miles per hour over the speed limit in Webster, New York. Rather than pulling over, she drove home while the patrol car followed with lights and siren activated. Body-camera footage later released to the public shows the district attorney  displayed her badge and emphasizing her position, refused multiple commands from the officer, called the Webster police chief during the stop, used profanity and told the officer “I understand the law better than you” and “I don’t really care.”

The incident generated local and national headlines. New York Governor Kathy Hochul referred the matter to the State Commission on Prosecutorial Conduct and local ethics bodies opened their own investigations.

The subsequent findings were harsh, albeit deserved.

The Monroe County Office of Public Integrity found her conduct was “rude at best, and more accurately described as abusive,” that her driving of a county vehicle and attempt to “secure unwarranted privileges or exemptions” violated county ethics codes, and referred the matter to the County Board of Ethics.

The Commission on Prosecutorial Conduct issued a 13-page report in 2025 recommending that Doorley be publicly censured, concluding that her behavior during the stop undermined public confidence in the justice system.

Doorley paid the speeding ticket and released a video apology, saying she took “full responsibility” for her actions and would undergo ethics training, but initially vowed not to resign.

By mid-2025, however, facing censure, she told the Commission it was “time for a new DA” and announced she would step down effective August 31, 2025, ending a 13-year tenure as Monroe County’s top prosecutor.

A Crime That Thrives in the Shadows

The Rochester case is not an isolated incident. Across the country, renderers and used cooking oil collectors report that “midnight pumping” operations now siphon off an estimated 8% of the U.S. used-oil supply, costing legitimate firms tens of millions a year.

A 2019 federal indictment in the South alleged that 21 defendants stole $3.9 million worth of used cooking oil from restaurants across three states.

In Pennsylvania, New Jersey, and New York, local District Attorneys offices have noted that grease theft has “caught the eye of organized crime,” with multi-state investigations looking at how recurring heists across the region might be linked.

According to a quick Google search, BBD has pleaded for years for more aggressive enforcement, telling other news outlets that thefts now hit roughly 30% of some regional customer bases at least once a year, and that the rate of theft has doubled in certain markets.

Altogether, these facts suggest a shadow market where small crews in box trucks, often out of state, roam restaurant parking lots at night. They drain tanks belonging to legitimate collectors such as BBD and sell the stolen oil into a chain of small, often opaque intermediaries. The product is ultimately aggregated, rendered, and sold into the global fuels system, making it indistinguishable from legitimately collected oil.

An Open Case and Unanswered Questions

Despite the detailed paper trail – GPS tracker data, surveillance video, victim depositions, bank records, seized cash, and a loaded handgun – the case has not yet produced a public trial verdict.

The Rochester cooking-oil case is about far more than a few vats of waste grease. It’s about how a supposedly low-value waste stream has become a multimillion-dollar target for organized theft, how that theft ripples through local businesses like BBD, and how gaps in enforcement can allow sophisticated criminal activity to flourish in the shadows.

Whether the federal case against Chen, Huang, Yan, Yang, Han, and Zhang ultimately ends in convictions, dismissals, or quiet plea bargains, it has already pulled back the curtain on a largely hidden economy, and raised uncomfortable questions about who, exactly, is willing to confront it.

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Federal Investigation Exposes Hidden Network Behind Cooking Oil Thefts Linked to Migrant Group