MINNEAPOLIS — A Michigan firefighter charged in a crash that killed two fellow firefighters and injured seven others told investigators he hadn’t slept more than 45 minutes in more than 24 hours and had used marijuana hours before the crash, Minnesota prosecutors said in charges filed Monday.

Michael Allen Johnson, 28, of Baraga, Michigan, showed “signs of impairment and combative behavior” when officers arrived at the scene just after 3 p.m. Saturday on Interstate 35W in the Minneapolis suburb of Blaine, according to a criminal complaint filed in Anoka County District Court.

Johnson later told investigators he believed he had fallen asleep at the wheel. He said he had been awake since 11 a.m. Friday and had not slept since then except for a 45-minute nap early Saturday. He also admitted to using marijuana early Saturday and to using cocaine two days earlier, the complaint said. Blood test results are pending.

Johnson was charged with two felony counts of criminal vehicular homicide.

The crew was from the Beartown Firefighters, which is based in Baraga on Michigan’s Upper Peninsula and is managed by the Keweenaw Bay Indian Community and the federal Bureau of Indian Affairs.

Johnson was driving the third of three vehicles in a convoy headed for Utah to fight a wildfire east of Park City. He told investigators he woke up to a passenger yelling. He veered off the right side of the road, overcorrected to the left, and struck the cable barrier between the southbound and northbound lanes of the freeway, the complaint said. The vehicle rolled over and the cab separated from the box of the truck.

One witness told investigators the convoy drove past him at about 80 to 90 mph in a 70 mph zone, the complaint said. The witness reported then seeing the third vehicle swerve into the right lane about three times, then swerve again across the lane onto the right side of the road before the crash.

James Shelifoe, 23, and Alan Swartz, 25, both of Baraga, were killed. Two survivors were in satisfactory condition Monday at Hennepin County Medical Center in Minneapolis. The other survivors were taken to Mercy Hospital in Coon Rapids and Unity Hospital in Fridley. A spokesman for the hospitals referred questions on their conditions to the tribal government office, where officials did not immediately return calls Monday.

Johnson remained jailed in Anoka, with a first court appearance scheduled for Tuesday. Prosecutors said they were not aware of him having an attorney who could comment on the charges.

The tribal government said in a statement Sunday that the injured firefighters were expected to recover. It said 11 other firefighters were also headed to the Box Canyon fire.

The tribe said on Facebook on Monday that the deceased firefighters would be returned home Tuesday. Shelifoe’s funeral is scheduled for Wednesday while Swartz’s funeral is set for Thursday. The fire departments in Baraga and nearby L’Anse were raising money to support those affected by the accident.