A massive search was stretching into its second day for a man who authorities say posed as a police officer and fatally shot a Democratic state lawmaker in her suburban Minneapolis home, an act Gov. Tim Walz called “a politically motivated assassination.

Authorities identified the suspect as 57-year-old Vance Boelter, and the FBI issued a reward of up to $50,000 for information leading to his arrest and conviction.

Authorities believe the fatal shootings of Minnesota state Rep. Melissa Hortman and her husband, along with the shooting of State Sen. John Hoffman and his wife, were politically motivated. Vance Luther Boelter has been identified by police as the suspected shooter.