A manhunt was under way on Saturday for Vance Luther Boelter, 57, who police said is a suspect in the killing of Democratic Minnesota state legislator Melissa Hortman and her husband, and the shooting of State Senator John Hoffman and his wife.

Police said the suspect had been seen earlier on Saturday wearing a light coloured cowboy hat, a dark coloured long sleeved collared shirt or coat with a dark bag.

The FBI offered a reward of up to $50,000 for information that could lead to his arrest.

David Carlson, 59, told Reuters that he has been sharing a house in Minneapolis with Boelter for a little more than a year and last saw him on Friday night. Then about 6am on Saturday, he received a text from Boelter.

“He said that he might be dead soon,” said Carlson, who called the police.

Carlson, who has known Boelter since fourth grade, said Boelter worked for an eye donation centre and stayed at the house because it was close to his job.

Carlson said he feels betrayed by Boelter and heartbroken for the victims, adding: “His family has got to suffer through this.”