Hunt for Victim’s Identity Baffling : Copter crash: Clues are scarce and data searches have proved fruitless in learning more about third man killed in accident.

Nobody knew who the man was or why he was standing there when the helicopter fell from the sky--or if he was standing at all. When the body was found beneath a car, there was speculation that he was an auto mechanic. Perhaps he dove under the car to get out of the way. Or maybe the explosion put him there.

If he had any ID with him, it was destroyed in the flames. All that remains of his clothing is a single white Fila brand athletic shoe, charred and melted.

Five days after the helicopter crash at Raymond and Vernon avenues that killed Los Angeles police veterans Gary Howe and Charles R. Champe, crash investigators said Tuesday that they have narrowed the cause of the accident to a mechanical failure, ruling out problems with the fuel mixture.

But identifying John Doe No. 121 may prove more difficult. “Right now we’re getting nowhere,” said spokesman Bob Dambacher of the coroner’s office, which is responsible for identifying the dead.

“There’s not a lot we can do right now,” agreed Detective Jim Lewis of the Los Angeles Police Department’s missing persons bureau. “We’re waiting for someone to report an individual missing who might be this John Doe. . . . It’s a waiting game.”

But coroner’s investigators usually find a way. Sharing a small office, coroner’s investigators Ed Ferguson and Nick Romero each year handle more than 500 John Does, Jane Does and Undetermined Does, usually just skeletal remains. By the end of the year, about 30 cases remain unsolved.

Ferguson is the man standing between John Doe No. 121 and a fate of eternal anonymity. Someone, he figures, might recognize the description: He was a male Latino between 30 and 45 years of age. He was 5-foot-8 and weighed about 210 pounds. He had a small gap between his two front teeth. He had cavities and there was no sign that he ever visited a dentist.

Because of the general description, the white Filas and the gap in the victim’s teeth, Ferguson believes someone might come forward. But only two calls have come in, he said, providing nothing more than the names of possible victims, not even descriptions. The callers left no return phone numbers, he said.

So far, Ferguson said, forensic studies have provided no leads. A computer search comparing the few readable fingerprints from the victim and those on file with Los Angeles police, the Sheriff’s Department, the state Department of Justice and the FBI has yielded no matches.

The next step, he said, is to compare the victim’s fingerprints with those on file with the U.S. Immigration and Naturalization Service. If he was a legal alien resident, the INS should have such records, Ferguson said. If he was an illegal alien, there are probably no such records.

A dental chart of the victim prepared by forensic odontologist Gerald Vale--a routine procedure in such cases--has similarly found no match in the National Crime Index Computer.

Because Vale found no signs of dental work, the chances of identifying him through dental records “are probably slim and none,” Ferguson said.

Even if a friend or relative provides strong evidence identifying the victim, it is unlikely that dental records or X-rays exist to corroborate the man’s identity. Corroboration, Ferguson said, will probably be made by fingerprints, if at all.

John Doe investigations tend to follow the law of diminishing returns, Ferguson said. Often, as in car accidents or house fires, investigators have a strong indication of who the victims are and set out to establish corroborating evidence.

But with little to go on at the outset and no progress in fingerprint and dental checks, John Doe No. 121 faces the increasing likelihood of receding to the files of unsolved cases as new ones take priority.

Last year, however, investigators used dental records to identify a body that had gone unidentified for a year.

“Then the problem,” Ferguson added, “is notifying next of kin.”