MANKATO — A recently unsealed report says a collision last year that killed two motorcyclists in North Mankato was caused by a teenager who veered into oncoming traffic after falling asleep behind the wheel.

The crash happened in July 2011, but the Minnesota State Patrol reports were sealed while the 17-year-old driver was going through the court process. The reports were released last week.

According to the reports, the teen told investigators he had about five hours’ sleep before working a shift for his family’s Arctic Ice business. He had just delivered an ice box to Fairfax and stopped in New Ulm to repair an ice box, and he was returning to the Mankato business.

He said he was feeling tired and estimated he “dozed off” for about two seconds before the collision.

“When I woke up, I was in the westbound lane and I was hitting or I had already hit the first motorcycle,” he said.

His truck slammed into motorcycles driven by Lars Albrecht, 49, of Rio Rancho, N.M., and Robert Austin, 61, of Canby, Ore. Both riders died. The truck also hit a car, severely injuring the two occupants.

A witness told investigators he was driving ahead of the motorcycles and watched the crash in his mirror. Donald Gieseke of New Ulm said it was unlikely the motorcyclists saw what was coming.

“The next thing I saw was the motorcycle tire — a cloud of dust and the motorcycle tire going straight into the air,” he said.

Gieseke said the teen’s head was down as his truck crossed the center line. He also said the teen made no attempt to swerve back into his own lane.

“Most of the time, when they come across, they tend to go back again,” Gieseke said. “But this one just kept coming.”

The Associated Press is not identifying the teen even though he’s now 18 because his guilty plea to a misdemeanor charge following the crash came in juvenile court.

A civil lawsuit filed by the victims’ families was settled out of court. Chris Rosengren, the teen’s attorney for the misdemeanor case, said the settlement is confidential and those involved can’t discuss it.

He also said his client has struggled to deal with the consequences of the crash.

“It was a real tragedy for him,” Rosengren said. “There was no question he was remorseful. He is a hard-working kid. … It was a terrible thing all the way around.”