The cause of Bobby Fuller's death at age 23 has remained a mystery for 50 years. The singer-guitarist, who led the Bobby Fuller Four to a Top 10 hit with "I Fought the Law," was found dead of asphyxiation in the front seat of his mother's car on July 18, 1966. The debate still rages whether the rising star committed suicide, died accidentally or was murdered.

Fuller and his band moved to Los Angeles from El Paso, Texas in 1964. The Fuller Four included brother Randy on bass, Jim Reese on guitar and drummer DeWayne Quirico. Del-Fi Records owner Bob Keane, who discovered Ritchie Valens, signed the band and served as their producer, manager and publisher. Though British Invasion groups began to dominate the charts, Fuller remained true to the raw style of American rockers like Valens, Buddy Holly and Eddie Cochran.

The Bobby Fuller Four scored a local hit in 1965 with "Let Her Dance." But it was the following year's "I Fought the Law" that won them national attention. The tune was written by Sonny Curtis, who joined the Crickets after Holly's death. The Crickets' 1960 original never charted but Fuller's version peaked at No. 9 on the Billboard Hot 100 on March 12, 1966.

A whirlwind of appearances followed as Keane hoped to capitalize on the record's success. The band had already packed Hollywood clubs like Ciro's and the Whisky A Go Go. Now they performed on TV's Hullabaloo and Shivaree and even turned up as Nancy Sinatra's backing band in the beach party flick The Ghost in the Invisible Bikini. Lasting success seemed inevitable, though Fuller was reportedly unhappy that the grinding tour schedule prevented the band from recording new material.

In the early hours of July 18, Fuller received a phone call and left his Hollywood apartment in his mother's blue Oldsmobile. Later that day Fuller's body was found sprawled on the front seat of the car, a gas can nearby. His body was doused with gasoline. The car had been in the parking lot outside the apartment for 30 minutes before his mother discovered the body.

Bruises covered Fuller's arms and body, prompting speculation that he had been beaten or dragged. Early news reports attributed Fuller's death to suicide by asphyxiation from the gas fumes. Los Angeles police apparently agreed; Fuller's associates weren't immediately questioned and cops on the scene disposed of the gas can without dusting for fingerprints.

The autopsy found no evidence that Fuller was beaten; the report stated that gas vapors and the summer heat probably caused hemorrhages on the body. The medical examiner checked both the "accidental" and "suicide" boxes on the report with a question mark next to each. But why would Fuller, at the cusp of stardom, kill himself?

Three months later the official cause of death was changed to "accidental asphyxiation." But other questions were never fully answered. If the car had only been in the lot for 30 minutes before it was discovered, how had Fuller's body reached an advanced state of rigor mortis? Had Fuller died somewhere else with his body then driven to the parking lot? A variety of wild theories followed: Fuller died accidentally after taking LSD at a party; Keane had Fuller killed to cash in on a large insurance policy he had taken out on the singer; and even that Charles Manson had a hand in Fuller's death. None of these theories has been proven.

In the 2015 book I Fought the Law: The Life and Strange Death of Bobby Fuller, authors Miriam Linna and Randy Fuller float a new theory: Morris Levy, the Roulette Records owner known for his strong-arm tactics and Mafia ties, was involved in Fuller's death. In 1966, Keane signed a deal with Roulette to distribute Fuller's music.

Randy Fuller believes that his brother may have been killed because he wanted to back out of a business deal with Levy, who died in 1990. “In July 1966, Bobby had had it,” Linna told LA Weekly. “The band was going to break up, he wanted out of their recording contract, he wanted out of the group. He was going to go solo. They were all supposed to meet at Bob Keane's, but Bobby didn’t turn up. Because he was dead.”

Fifty years later, many still believe the cause of Bobby Fuller's death remains unexplained. Still, his music lives on. "I Fought the Law" has been covered live or in studio by classic rockers that include Bruce Springsteen, Tom Petty, the Grateful Dead and the Ramones. In 1979, the Clash won early success in the States with the release of "I Fought the Law," their first U.S. single.