The man who was shot twice and critically wounded Monday in Wheaton when he approached the van of a motorist he thought was in trouble was identified yesterday by Montgomery County police sources as Gregory Dapron, 20, of Wheaton. Dapron, an electrical technician, did not know the driver and was just trying to help him get his van out of the snow, according to Dapron's roommate.

When Dapron walked up to the van at Grand Pre and Bel Pre roads about 5:30 p.m., its driver allegedly shot him in the leg and the abdomen with a handgun, then fled in the van, according to police spokesman Cpl. Philip Caswell.

A suspect, James Robert Shell, was arrested later Monday night and taken to Clifton T. Perkins Hospital Center for mental observation. A warrant charging him with assault with intent to murder was issued yesterday, police said.

After the shooting, police said, the van was driven a few miles and abandoned at a service station near the Cloverly Shopping Center on New Hampshire Avenue. Police said they later found a gun in the vehicle.

One witness told police that the van's driver then walked across the street and was hit by a passing car, although he was not seriously injured.

The van's driver then forced his way into an elderly couple's home, police said, and ordered them to drive him to South Carolina. The couple apparently convinced him he needed medical attention and took him to Montgomery General Hospital, according to police. Police were called after psychiatrists at the hospital interviewed the man. Police refused to release the couple's name.

Dapron was in critical but stable condition yesterday at Suburban Hospital, according to a hospital spokesman.