A Metro mechanic was crushed to death early yesterday morning at a transit authority garage when an empty bus rolled forward and pinned him against the bus he was refueling, D.C. police said.

The victim, In Hoe Kim, 51, of the 9000 block of Carol Street in Landover, was crushed between the two buses at 12:50 a.m. after one bus, which had been parked and left with its motor running, lurched forward, according to Detective John Killian of the traffic division. Killian said the parking brake had not been set.

One Metro employe jumped aboard the moving bus and tried to stop it, according to Metro spokesman Marilyn Dicus. Another employe yelled at Kim to get out of the way, but Kim apparently did not hear him or did not have time to move, she said. The bus picked up speed as it moved down a slight incline before striking Kim, police said.

Metro officials said they have no explanation for the accident, which occurred at Metro's Bladensburg Garage, 2250 26th Street NE. They said they are awaiting results of an internal investigation.

Kim was declared dead at Washington Hospital Center at 1:26 a.m. Deputy Medical Examiner Stuart Dawson said he died of injuries of the upper body.

Alex Kim, 24, one of the victim's two sons, said a Metro official telephoned the family but could not explain who was responsible. "Nobody knows who parked the bus behind my dad, or nobody would say," said Alex Kim.

The victim, a native of Korea who moved to this country with his family 10 years ago, worked at the garage for six months, Dicus said. Before that, he helped run a Prince George's County service station.