Attorney General Jeff Sessions questioned the legitimacy of cannabis regulatory structures in a letter sent to Colorado Gov. John Hickenlooper two weeks ago.

In the letter, Sessions cited data from a September 2016 report by the Rocky Mountain High Intensity Drug Trafficking Area, a federally funded agency operated from the White House’s Office of National Drug Control policy. The report claimed increases in highway patrol seizures, youth use, traffic deaths, and emergency department visits since social cannabis was legalized in 2014.

The letter was a response to an April 3rd letter from Hickenlooper and the governors of Alaska, Oregon, and Washington which encouraged AG Sessions to engage with legal cannabis states before changes to regulatory and enforcement systems were made.

The correspondence between the Department of Justice and Colorado officials are part of an ongoing discussion between states which legalized cannabis, and the department which is reviewing existing cannabis policy.

Two weeks ago, the Justice Department met with 20 officials from a variety of Colorado agencies to discuss cannabis regulation. They presented charts, data, and information on cannabis regulation and addressed public health and law enforcement concerns.

“We want to engage in a dialogue with the attorney general, the White House, the Justice Department about the most effective ways that the state and the federal government can work together to protect our priorities of public safety, public health and other law enforcement priorities,” Mark Bolton, cannabis adviser to Gov. Hickenlooper, said.