On a splendid fall afternoon, a District man left his blue minivan running yesterday while he ducked inside a friend's Northwest Washington apartment. When he glanced outside, his 1990 Ford Aerostar minivan was gone. And so were his sons, 3 and 4, who had been sleeping in the back seat, D.C. police said.

Frantic, the 27-year-old man dashed outside. His friend called police. About 20 minutes later his children were found unharmed in a back yard a few blocks away, police said. As of last night, the thief and the van were nowhere to be found.

Lt. Jimmie Riley said the van was taken about 5:20 p.m. in the 1400 block of Newton Street NW, near the Mount Pleasant neighborhood. Shortly after, the thief dropped the children off in the 3500 block of Holmead Place NW.

A woman who lives on that block heard "children calling, 'Mommy, Mommy,' " Riley said. The woman went outside but couldn't communicate with the children because they were speaking Spanish, Riley said. So she took the boys to a neighbor who speaks Spanish fluently, he said.

Police drove the father to the house. "He was crying; he was very happy to see his children," said Riley, who witnessed the reunion.

As for the children, he said, they were happy to see him, "but they were relatively cool. They were a bit confused. He was probably the more emotional one."

Police declined to release the name of the father.