Officials named the last unknown victim of the ’92 riots. Now they want to solve the mystery of his death.

It is the coldest of cold cases with few clues.

He was known as John Doe No. 80 for a quarter-century after his charred remains were found inside a Pep Boys torched at the height of the 1992 Los Angeles riots.

But with his identity now confirmed and the release of a photograph of a dark-haired youth with a serious expression, investigators say they are intent on solving the mystery of his death, which was ruled a homicide.

In April, using a single print from his left middle finger and records of a prior arrest, authorities identified the man as Armando Hernandez, a Mexican citizen.

On Thursday, officials said family members revealed that his real name is Miguel Armando Quiroz Ortiz, who was 18 at the time of his death.

Armed with a positive identification and a handful of clues, the LAPD Robbery-Homicide Division’s Cold Case Unit, which cracked the Grim Sleeper serial killer case and dozens of other decades-old murders, is looking for answers.

“This is one of the toughest cases,” Det. Luis Rivera said. “All we have is a single shell case near the body, and we don’t know if it is connected to his death.”

Rivera said there is no evidence Ortiz was shot and so far no match of the spent .38 casing to other crimes in a national shell casings database.

Ortiz officially died of smoke inhalation and carbon monoxide poisoning as flames consumed the Pep Boys auto shop on Vermont Avenue. Rivera said evidence suggests Ortiz was alive when the fire started.

Because the fire at the Pep Boys was deliberately set, his death was ruled a homicide. He joined the list of 23 riot-related homicides that have never been solved.

Rivera said they hope the photo triggers a recollection from someone who may have known Ortiz or may have seen him at the auto store.

“Maybe someone saw something that day of what happened to him inside the store,” Rivera said. “Somewhere out there is someone who knows what happened to Miguel Ortiz.”

Family members told investigators that Ortiz came to the U.S. in 1989 to find work. But after several contacts, he was never heard from again. Rivera said Ortiz was accompanied north by another man, whom police would like to identify and interview.

Ortiz was the only remaining unidentified victim among the more than 60 people who lost their lives in one of the deadliest riots in U.S. history.

His body was so badly burned that coroner’s investigators were left with only some teeth and the partial fingerprint. Every few years, they would try to match the fingerprint.

This year investigators sent the print to an FBI squad that specializes in identifying victims of disasters such as Hurricane Katrina and the Sept. 11 terrorist attacks. Ortiz had a few minor arrests in Los Angeles County and Anaheim, allowing FBI investigators to make a match.

Mexican officials distributed his photo across the nation to see if it matched that of any missing people.

A connection was made to a Facebook page for Miguel Ortiz, a man who had gone missing from Oaxaca, Mexico. Family members exchanged documents with investigators and a positive identification was finally made for John Doe No. 80. Although Ortiz was reported missing in Mexico, no missing persons report was ever made in the United States, Rivera said.

Ortiz was working at a bakery on Florence Avenue, near the auto store, at the time he died, officials said.

“He had been sending money back to his family in Mexico, and it suddenly stopped in April 1992…. They had a phone number and address and the mother tried calling. There was one phone in their village back in Mexico,” Rivera said.

Ortiz was inside the auto repair shop, just north of Slauson Avenue, when it was set on fire sometime after the riots started on April 29, 1992. His body was not found until May 2 about 30 feet from the building entrance.

Jorge Macias, now an LAPD lieutenant, was a young officer patrolling the area at the time when he was flagged down by a 10-year-old boy.

“He pointed to a burnt-out pile of rubble on the west side of the street,” Macias recalled. “The boy pointed beyond some fallen girders, which had fallen at acute angles ostensibly from the roof, when the roof had given way, sealing the victim’s fate. I had to duck-walk under the maze of obstacles, including the blackened steel beams, until I reached the remains.”

Rivera and partner Det. Veronica Conrado ask that anyone with information on Ortiz contact them at 1-877-527-3247 or outside business hours at 1-877-LAPD-24-7. Tips can also be made anonymously at 1-800-222-TIPS.

richard.winton@latimes.com

Twitter: @lacrimes