TOPEKA, Kan. (AP) — A former federal prosecutor who’s been an executive in a company that invests in medical marijuana has launched his campaign as a Democratic candidate for the U.S. Senate in Kansas.

Kansas City-area attorney Barry Grissom entered the race Monday after months of hinting that he would run. Four-term Republican Sen. Pat Roberts is not seeking re-election in 2020.

Grissom served as U.S. attorney for Kansas from 2010 to 2016 as an appointee of Democratic President Barack Obama. He has since served as corporate counsel and a vice president for Nevada-based Electrum Partners.

Grissom jumped into the race after state Sen. Barbara Bollier said she may seek the Democratic nomination. Bollier won her Kansas City-area district as a moderate Republican and switched parties last year.