A self-identified California survivalist was sentenced Monday to three consecutive life sentences, without the possibility of parole, in the murders of a couple sleeping on a beach in 2004, as well as the 2017 murder of his own brother.

Shaun Michael Gallon, 40, pleaded no contest last month to the murders of Lindsay Cutshall, 22, and Jason Allen, 26, who were shot to death between Aug. 14 and Aug. 16, 2004, as they slept on Fish Head Beach near Jenner in Sonoma County.

The case remained unsolved until 2017, when Gallon was accused of using a rifle to kill his younger brother, 36-year-old Shamus Gallon, in the Forestville home they shared with their mother.

Following his arrest, Shaun Gallon confessed to the Allen-Cutshall homicides. He pleaded no contest June 13 to all three killings.

At the time, Sonoma County officials said there was no apparent motive for Gallon to shoot his brother.

"There doesn't appear to be an altercation of any significance that led to the shooting," Sgt. Spencer Crum told the Press Democrat.

Even prior to his brother's slaying, Shaun Gallon's name had long been on law enforcement's radar. The San Francisco Chronicle reported he was well-known for his erratic behavior, and his rap sheet was a long one.

He was convicted in 2009 of assault with a deadly weapon for shooting an arrow at a man in Guerneville, the Chronicle reported.

His Facebook page shows multiple photos of homemade bows and arrows, as well as a photo of hiself with a spear he made.

"Further, Gallon was also alleged to have attempted to kill a Monte Rio man in June 2004 by using a disguised homemade explosive device, and seriously injuring a second unintended victim when it detonated," a news release from the Sonoma County District Attorney's Office read.

Gallon was charged in 2017 with felon in possession of a firearm and ammunition, as well as possession of an illegal assault rifle, the district attorney said.

The charges to which Gallon pleaded no contest are lengthy, court records show.

"There were multiple special allegations and enhancements alleged against Gallon, including that he murdered multiple victims, that he committed great bodily injury on those victims, that he used a firearm to inflict great bodily injury on each of his murder victims and that he had suffered a prior 'strike' conviction in 2009 for assault with a deadly weapon," Ravitch's news release said. "In his change of pleas, Gallon admitted all charges and enhancements."

Gallon waived all rights of appeal by entering into the plea agreement. Ravitch said the agreement was reached after a review of the records, a review of mitigating material offered by the defense and talks with the victims’ families, as well as the surviving victims of Gallon’s prior crimes.

Photos recovered from their camera shows they took photos of one another in front of the Golden Gate Bridge and Alcatraz, the newspaper reported.

They then headed north in Cutshall’s red 1992 Ford Tempo for the Sonoma coast, where they found themselves in Jenner, a village Allen had visited a few years earlier. Several witnesses, some conflicting, reported seeing the couple along the way as they stopped for gas and other items.

A front desk clerk at the Jenner Inn told police the couple showed up there either Friday, Aug. 13, or the following night. Though the couple ate at the inn, there were no available rooms, so they said they would camp outdoors instead, the Chronicle said.

The manager, who declined to give her name, said she chatted with the couple again the following morning when they came in for breakfast.

"I asked them if they were having fun," the woman told the newspaper. "They said they stopped in San Francisco. They were just a happy couple trying to get away for the weekend."

Various accounts indicate Allen and Cutshall were told Fish Head Beach would be a good spot to camp, even though it was illegal to sleep on the beach there.

Police believe it was the night of Aug. 14, 2004, when the couple parked Cutshall's Tempo in a pullout along nearby Highway 1 before setting up their gear on the beach. According to Sonoma magazine, both made notations in a visitor's log kept near the beach.

"As I stir this mac and cheese, I think to myself, 'What a wonderful life,'" Allen wrote. "I've just spent two awesome days with my fiancée, Lindsay. Can life ever be so perfect? Only with a person who is so great. God gives me this privilege in life and He has given me a wonderful woman to enjoy it."

"The sun is going down in the horizon," Cutshall wrote, according to the magazine. "All I see is the beams shining on the cliff face. And I know that God is awesome. I look around and I see his creation all around me."

Authorities believe the couple was killed, each by a single rifle shot to the head, that night or early the following morning as they slept in their sleeping bags, their Bible nearby.

Family and friends grew concerned when the couple had not turned up back at the Christian camp by Sunday. According to the Chronicle, Lindsay was due to fly home a week later to begin planning her wedding.

A missing person report was filed Monday, Aug. 16, by friends at the camp.

The couple's bodies were found two days later, first spotted by deputies in a Sonoma County Sheriff's Department helicopter sent up to search for a man stuck on a cliff near Jenner, the Chronicle reported.

Instead, the spotters saw two bodies in bloodstained sleeping bags.

With no apparent motive -- there were no signs of robbery or sexual assault at the scene -- detectives were stymied for years.

It would take another 13 years before investigators learned what happened or why.

‘I went crazy’ 

A Sonoma County Probation Department report, obtained by the Press Democrat, paints a disturbing portrait of Gallon's life and shows ways in which his family shielded him from arrest before he killed his brother.

Gallon’s father, David Gallon, admitted to police he got rid of his son’s guns in 2004, a week after Allen and Cutshall were found slain. Shaun Gallon, who had been arrested on unrelated weapons charges, called his father and asked him to dispose of the weapons.

David Gallon told investigators he did so "because he feared (Shaun) Gallon was unstable," the document says.

The records show Shaun Gallon became a potential suspect in the double homicide on the beach after deputies found him near a beach in Guerneville with a loaded, stolen gun in the pocket of his camouflage jumpsuit.