When William H. Miles Jr.'s Cadillac broke down near the Alexandria city limits Dec. 21, he abandoned it and headed home.

Police said he was spotted a short time later less than a mile from his home in Baileys Crossroads section of Fairfax County.

But that's apparently as far as he got. He hasn't been seen since.

Now, county police suspect foul play might be behind the 10-day disappearance of Miles, 56, a retired government maintenance worker.

At 9 p.m. on Dec. 21, less than six hours after Miles was last seen, two burglars burst into his home at 5736 Poplar La. and ransacked it.

A woman neighbor, hearing loud barking from Miles' dog, went to the house and surprised the intruders as they were lugging away a television police said.

The startled burglars dropped the television and fled. Police said they also found Miles' keys near where the television was recovered, prompting investigators to theorize that the thieves had stolen them from Miles.

Investigator C. J. Kozloff said the discovery of the keys is the chief reason police suspect foul play in the disappearance.

The recovery of Miles' keys also worries a nephew, Gilbert Bigelow, 32, who lives on the same street as his uncle.

"That's what's curious about the whole thing," Bigelow said yesterday. "He had his keys with him."

Bigelow said it is unusual for his uncle to be away from home for so long. Miles lives alone in his two-bedroom house. His wife is dead, and he had a son in the Army.

"He really has no place to go," Bigelow said. "He usually stays close to home. I can't imagine where he could be."

Miles, a black man, stands a little over six-feet, weighs 190 pounds and has brown eyes and brown hair. The day he disappeared he was wearing a green cap, green jacket, a brown flannel shirt and brown trousers.

His family has offered a $500 reward for anyone providing information resulting in his safe return.

Anyone with information is asked to call Investigator Kozloff at 691-2587 or the police emergency number, 691-2131.

Bigelow said his uncle was capable of protecting himself. The owner of several guns, it's likely that Miles had a pistol with him the day he disappeared, Bigelow said.

"The only think I can imagine," Bigelow said, "is that somebody picked him up. God only knows what happened then ."