Shaun Gallon, 38, was questioned in the murders of Lindsay Cutshall, 22, and her fiance Jason Allen, 26. The two victims were found next to each other on a driftwood-strewn beach, still zipped into their sleeping bags, on Aug. 18, 2004.
ARCHIVE VIDEO: 2004 report on couple killed on beach in Sonoma County
Sonoma County Sheriff Steve Freitas said investigators have interrogated Gallon, of Forestville, who is in custody in the March fatal shooting of his brother. Gallon knew things about the killings that no one who wasn't involved could have known, the sheriff said, and authorities have also found corroborating evidence.
"We feel confident we have Jason and Lindsay's killer," Freitas said of the young couple, whose mysterious killings drew national attention.
Lindsay Cutshall and Jason Allen were youth counselors at a Christian camp East of Sacramento, and were engaged to be married.
Police knew only that they died instantly from two close range gunshots to their heads while they slept. There was no indication of a struggle or a robbery. There was also no obvious motive, and for 13 years it remained that way.
Freitas said authorities believed the killing was random, and that there was no previous connection between the two and the suspect.
Cutshall, a native of Fresno, Ohio, and Allen, from Zeeland, Michigan, were on a weekend trip.
Sheriff's deputies described Gallon as a survivalist with a violent history. In 2010 a judge sentenced him to three years in prison after shooting an arrow through the roof of a car, hitting a man inside. He had been in jail since March, charged with shooting and killing his younger brother. Gallon's home was searched Friday, possibly for a murder weapon used in the Jenner killings. The sheriff's office says he has always been a person of interest, and detectives never ruled him out as a suspect.