Maine’s congressional delegation is asking the U.S. Department of Justice to shut down illegal Chinese-run marijuana growing operations in the state, citing a report last week that there could be as many as 270 such operations in the state worth more than $4 billion.

A letter signed by Maine’s senators and representatives to Attorney General Merrick Garland this week comes in response to a report on a conservative news website that sourced the information to a leaked memo.

“These reports of illegal growing operations within the state are alarming, and we are writing to request additional information about what the DOJ is doing to address this situation,” the delegation wrote.

Sens. Susan Collins and Angus King, and Reps. Chellie Pingree and Jared Golden posed a series of questions centered mostly around what the government knows about these operations and what it plans to do to disrupt them.

Maine law allows for the adult use of marijuana, but the industry is highly regulated and taxed. There are 144 licensed legal grow sites across the state, according to the Office of Cannabis Policy, or about half of the alleged total of illegal sites connected to Chinese investors. Only 89 of the 144 legal grows are active.

A report by the Daily Caller last week cited a leaked confidential memo that it said was distributed by U.S. Customs and Border Protection officials and detailed widespread Chinese marijuana growing operations in Maine that were not being regulated or taxed. The memo said profits from these operations are being sent back to China or used in other criminal activities.

Federal officials have not provided additional details about the memo or confirmed that it is authentic.

“It is the policy of CBP to neither confirm nor comment on potentially leaked information,” an agency spokesperson wrote in response to questions from a reporter Thursday.

Matthew Felling, a spokesman for King, said Thursday that the Justice Department has not yet responded to the delegation’s letter. He said Maine’s members of Congress are “still in the question-asking phase.”

Shannon Moss, a spokeswoman for the Maine Drug Enforcement Agency, would not comment on the delegation’s letter or any active investigations.

“I can tell you that as a matter of course, when the Maine Drug Enforcement Agency uncovers, becomes aware of, or receives intelligence about illegal drug activity in Maine, it works closely with federal and local partners to determine the best course of action to disrupt and dismantle illegal drug activities in Maine and to ensure the successful prosecution of such activities,” she said in an email.

Similarly, Danna Hayes, with the Office of the Maine Attorney General, said that office “continues to prosecute cases involving illegal marijuana cultivation and trafficking, specifically where the conduct cannot be addressed through regulatory responses by the Office of Cannabis Policy.”

Maine would not be the only state dealing with illegal growing sites connected to China.

Politico reported this year that Chinese involvement in American cannabis cultivation has been increasing, citing evidence of large numbers of cultivation operations in states such as Oklahoma, California and Oregon. Investigators in others states have linked the operations to Chinese entities, some connected to organized crime, that are either investing in operations or supplying workers, or both.

In Oklahoma, an official said that of the more than 800 cannabis farms that have been shut down for operating illegally in the last two years, 75 percent were linked to China. There also is evidence that some of that state’s licensed facilities have Chinese ties, the official told Politico.

A news website in San Francisco also reported recently that Chinese groups are behind many of the illegal cannabis operations in Northern California.

Maine has sometimes struggled to police illegal marijuana grow operations since the legal market launched and there have been several high-profile investigations in recent years. None has been linked to China, at least publicly.

In June, deputies with the Penobscot County Sheriff’s Office seized 3,400 individual marijuana plants and 111 pounds of processed marijuana from an operation in Carmel that was not licensed or permitted.

Last October, a marijuana-growing operation in Embden that was destroyed by fire was operating illegally. The fire was at least the third in central Maine in 2022 involving a marijuana-growing operation. The other two were in Vassalboro, and one of them also was an illegal operation.

Alexis Soucy, a spokeswoman for Maine’s Office of Cannabis Policy, said that the office does not pursue illegal operations and has authority to regulate only activities within the state’s medical and adult use cannabis programs and among these programs’ licensed operators.

“Unregulated and illicit cannabis operations are threats to the work that OCP does, to the livelihood and financial well-being of our licensed and compliant businesses, and to customers and patients in Maine who choose to use cannabis,” she said.