On the eve of his trial for both the 2017 murder of his brother and the highly publicized 2004 double homicide of a couple who were camped on a beach in Jenner, 40-year-old accused killer Shaun Gallon entered a new plea of no contest Thursday.

Gallon was identified as a suspect in the 2004 killings in May 2017, shortly after his arrest for the March 2017 murder of his brother, Shamus, at the family home in Forestville. Gallon had been a person of interest in the older case for many years, but investigators had not found enough evidence to connect him to the seemingly random slaying. As the Santa Rosa Press-Democrat reported, Gallon sat in a Sonoma County jail for a number of weeks before he wrote a note to detectives indicating he was willing to talk. Investigators then say he revealed information about the case that only the killer could have known. As of a year ago, he was still pleading not guilty.

Christian youth camp counselors Lindsay Cutshall, 22, and her fiance Jason Allen, 26, were found dead in their sleeping bags on Fish Head Beach in August 2004. They had been on a three-day sightseeing trip after working at a white-water rafting camp in El Dorado County, and were planning to return home to the Midwest. There were no signs of robbery or struggle, and after making headlines across the Bay Area, the case went unsolved for 13 years. Investigators say that Gallon was known in the Russian River area even at the time — when he was 25 — for his strange behavior and run-ins with the law. The Press-Democrat describes him as a "self-taught survivalist and weapons fanatic" who was arrested in a 2004 case involving a homemade bomb, and a 2009 case in which he shot a man with a homemade bow and arrow, for which he served three years in prison. A Facebook photo below from around 2016 showed him with another weapon, and the caption, "CHECK OUT THIS NICE SPEAR I MADE."

The 2004 bomb incident was apparently targeting John Robles of Monte Rio, however it ended up injuring only his girlfriend, 27-year-old Parvoneh Leval, as the Sonoma West Times & News reported at the time. That incident happened just two months before Cutshall and Allen were killed on a secluded beach a few miles down the road.

Gallon's motive in the killings was never known or publicized, but Sonoma County Public Defender Kathleen Pozzi told the Press-Democrat, "There is no question that he suffers from mental illness."

Lead sheriff’s detective in the case Joey Horsman tells KPIX/CBS SF, "[Gallon] was very candid about the crimes he committed." He adds that investigators "unequivocally knew" that Gallon was guilty.

Sheriff’s Lt. Tim Duke concurs, saying to KPIX, "It’s a win win. The evidence matches his admission and he confessed."

Gallon is now scheduled for sentencing on July 15. As part of his plea deal, District Attorney Jill Ravitch has agreed not to seek the death penalty.