GRAND RAPIDS, Michigan (AP) — The former head of a Michigan marijuana licensing board pleaded guilty to bribery Tuesday, acknowledging he accepted at least $110,000 in exchange for approving applications for the lucrative business.

Rick Johnson’s appearance in federal court in Grand Rapids was a remarkable fall. Years ago he was a powerful state lawmaker, serving as speaker of the Republican-controlled House from 2001 through 2004.

The investigation so far has centered on corruption at the marijuana board before it was disbanded in 2019. The board reviewed and approved applications to grow and sell marijuana for medical purposes.

A Detroit-area businessman, John Dalaly, pleaded guilty last week. He said he provided at least $68,200 in cash and other benefits to Johnson, including two private flights to Canada.

Two lobbyists, Brian Pierce and Vincent Brown, have agreed to plead guilty to conspiring to pass bribes to Johnson. All four men are cooperating with the FBI, which could help them at sentencing.

Johnson’s plea agreement states that he must provide investigators with information about “any and all criminal activity of which he is aware” and testify in court or to a grand jury if necessary. That provision isn’t limited to his work on the marijuana board.

“We may or may not bring future charges in this case,” US Attorney Mark Totten told reporters outside court. “What I can say is that the investigation and prosecution of public corruption is a priority for our office. We will follow it wherever we find it.”

Prosecutors agreed not to bring charges against Johnson’s wife, Janice. Dalaly said Rick Johnson told him to hire her to work on license applications.

Governor Gretchen Whitmer abolished the medical marijuana board a few months after taking office in 2019 and put oversight inside a state agency.

Michigan voters legalised marijuana for medical purposes in 2008. Voters approved the recreational use of marijuana in 2018.