New details about Vance Boelter, accused of fatally shooting a state lawmaker and her husband, were revealed in court documents.

Investigators found a cowboy hat near the vehicle and were working to determine whether it belongs to Boelter.

Prosecutors developing the state's case against Vance Boelter intend to pursue first-degree murder charges, Hennepin County Attorney Mary Moriarty said Monday. Second-degree murder and attempted murder charges filed Saturday against Boelter allowed for the issuance of a nationwide arrest warrant, Moriarty explained.

Vance Luther Boelter, 57, opened fire on Mark Hortman as police pulled up, then exchanged gunfire and fled, investigators said.

Live updates: Rep. Melissa Hortman, husband assassinated; suspect Vance Boelter at large originally appeared on Bring Me The News. Melissa Hortman, the top Democratic lawmaker in the Minnesota House, was shot and killed in a suspected politically-motivated assassination along with her husband early Saturday.

Murder charges have been filed against Vance Boelter in the suspected assassination of State Rep. Melissa Hortman and her husband Mark, with the 57-year-old also charged with the attempted murder of Sen.

A dedicated volunteer who taught Sunday school and loved dogs. A lawyer who served as a Girl Scout Leader and worked at her dad’s auto parts store. A mother and wife whose husband was killed alongside her.

State Rep. Melissa Hortman and her husband were killed, and state Sen. John Hoffman and his wife were injured, in what officials called a targeted attack.