A state trooper who had stopped to help who he thought was a stranded motorist was shot and killed Thursday by the man, who then reloaded the shotgun and killed himself, state police said.

Master Trooper David Rich was shot in the chest by Joseph M. Vultaggio Jr., 21, of Gaylord, Mich., on U.S. 24 in northern Indiana, state police Sgt. Tony Slocum said.

Slocum said Vultaggio was driving a sport-utility vehicle that his father had reported stolen on Wednesday.

Rich, 41, was an 18-year veteran of the state police. He was married with a 7-year-old daughter and twin 3-year-old sons, Slocum said.

"If that guy needed help, he would have gave him his shoes, his pants," Slocum said. "He would have done anything to help him, just as he's done here on many occasions at the post."

The shooting prompted authorities to shut down the four-lane highway in both directions around the scene, about 40 miles southwest of Fort Wayne, for more than two hours.

Rich is the first state trooper killed in a line-of-duty shooting since another officer was fatally shot in December 2003 after he stopped to a check a vehicle parked on an interstate exit ramp in Gary.