Police Seek Runaway Boy Whose Friend Was Slain : Search: The 11-year-old may have witnessed the slaying or been a victim, authorities say. The youths left Yucca Valley homes last month.

An 11-year-old Yucca Valley boy is being sought by authorities who are not sure whether he is a witness to the murder of his friend after both of them ran away from home last month or whether he has also fallen victim to foul play.

The boys disappeared Nov. 20--the day after they ran away from their homes over arguments with their mothers, Sgt. Larry Brown of the San Bernardino County Sheriff’s Department said. The arguments were prompted by their mothers’ belief that the boys were suspects in some burglaries, he said.

The body of 14-year-old Arthur Leroy Leftwich was discovered Dec. 16 in a dry desert wash north of Yucca Valley, but there has been no sign of his young sidekick, Robert Martinich, Brown said.

Investigators don’t know whether Martinich is alive--or whether he may have witnessed his friend’s death and is holed up somewhere in the desert near Yucca Valley and Twentynine Palms.

Confounding the investigation, Brown said, is that no one has reported seeing either boy since the day after they ran away.

“We’re trying to contact everyone they possibly knew,” Brown said. “We feel certain somebody has had to have seen these kids, and that will lead to solving this: who saw them last, and with whom.

“This is an unusual case without a doubt: Two boys run away, aren’t seen for a month, and then one turns up dead.”

Brown said investigators are withholding the details of Leftwich’s death except to say his fully clothed body was found in desert vegetation in the Pipes Canyon wash area of Flamingo Heights. The closest residences are three-quarters of a mile away.

The 14-year-old may have been dead for up to 10 days before his body was found, Brown said.

“Without a doubt, it was homicide,” Brown said. “But one of the few investigative leads we have is that only we, and the crook, know how he was killed.”

He described the boys as streetwise and said they apparently agreed to run away together after each fought with his mother.

Investigators are perplexed that no one in the Yucca Valley-Twentynine Palms area has come forward to say they saw the boys during the three weeks from when they ran away and when Leftwich was apparently killed, and that no one has seen the younger boy in the last two weeks.