Maine’s congressional delegation is again calling for the U.S. Department of Justice to investigate and help the state crack down on illegal marijuana growing operations in Maine that benefit Chinese investors.

In a letter dated Jan. 25 to U.S. Attorney General Merrick Garland, U.S. Sens. Susan Collins and Angus King, and U.S. Reps. Chellie Pingree and Jared Golden urged the Justice Department to provide Maine law enforcement agencies with additional help shutting down the operations.

This week’s letter is a followup letter to one the delegation sent in August. It said illegal growing operations are detrimental to businesses that are complying with Maine marijuana laws. One dispensary owner estimates that these illegal operations are selling marijuana for half the price she pays to legal growers. The price difference is unfair, they say.

The issue gained attention in August when an internal memo by the U.S. Border Patrol revealed that there were an estimated 270 illegal Chinese marijuana growing operations in Maine taking in an estimated $4.37 billion in revenue.

The delegation asked Garland what his agency planned to do about the illegal operations.

Since then, there have been multiple raids on suspected operations across the state. Law enforcement has arrested eight people and seized more than 4,400 cannabis plants from four growing sites in Belgrade, China and Cornville alone.

Three people were arrested on Jan. 17 during an illegal marijuana bust at a home on West Ridge Road in Cornville. More than 750 plants and 90 pounds of processed marijuana were seized during the raid. The Somerset County Sheriff’s Office arrested 75-year-old Huansheng Mai, 63-year-old Yuling Mei, and 68-year-old Yiming Hu.

Each was charged with illegal cultivation of marijuana and unlawful trafficking in scheduled drugs with more than 500 plants. The charges are Class B offenses.

“While these illegal operations may be secretive, they are often not hard to spot for neighbors in these tightknit communities,” the delegation states in their letter to Garland. The arrests and seizures in Belgrade occurred following “community complaints.”

Court documents from the case in Carmel showed that the house rented by one defendant was billed $6,900 a month for electricity, one indicator of a large scale growing operation.

“We applaud Maine law enforcement for their continued efforts to investigate and shut down these illegal operations, and we encourage the DOJ and other federal partners to provide additional support for these efforts,” the delegation says in its letter to Garland. “These illegal growing operations are detrimental to Maine businesses that comply with state laws, and we urge the DOJ to shut them down.”

Maine law allows for adult use of marijuana, but the industry is highly regulated and taxed. There are 144 licensed legal growing sites across the state, according to the Office of Cannabis Policy.

Only 89 of the 144 legal operations are active. A spokesperson for the Office of Cannabis Policy did not respond to questions Monday night.

Maine’s Cannabis Legalization Act, approved in 2016 by Maine voters, established a regulatory framework governing adult cannabis use in Maine. The law specifies regulations for tracking cannabis plants and product, enforcement and compliance, health and safety data, labeling and packaging, and licensing and fees.

The delegation raised a number of questions in the most recent letter, including what the Justice Department is doing to address the illegal operations, whether it is aware that these operations are owned by the Chinese or other foreign governments, and whether the profits from these operations are being funneled back to the countries of origin.

They also want to know how much support the department is providing to Maine agencies working to shut down these operations.

When Maine State Police or the Maine Drug Enforcement Agency uncovers, becomes aware of, or receives intelligence about illegal drug activity, it works closely with federal law enforcement to determine how best to “disrupt and dismantle illegal drug activities,” said Shannon Moss, spokesperson for the Maine Department of Public Safety.