The Sonoma County Sheriff's Department didn't immediately respond to requests for confirmation of the parents' comment.
Karen Scarseth, the mother of 21-year-old Nicholas Edward Scarseth, told The Associated Press in a phone interview from Chippewa Falls, Wis., that her son was allowed to leave Tuesday night after telling Sonoma County detectives he had never met the couple.
"It was all a big mixup," she said, "a big hullabaloo about nothing."
The sheriff's department has devoted dozens of detectives to investigating the slayings of Lindsay Cutshall, 23, and her fiance, Jason Allen, 26, who were found Aug. 18 shot to death in their sleeping bags on a remote beach. No weapon has been found.
Cutshall, of Fresno, Ohio, and Allen, of Zeeland, Mich., were reported missing Aug. 16 after they failed to show up at a Christian adventure camp in Coloma, about 40 miles east of Sacramento. They had been working at the camp as whitewater rafting guides for the summer. Autopsies indicated they were killed either Aug. 16 or Aug. 17.
Scarseth's parents said two Sonoma detectives showed up at their house in Chippewa Falls to apologize for naming their son in a police alert. As it turned out, the tip that led detectives to their son came from a person who reported seeing the slain couple after their bodies were already in the morgue, they said.
The parents said the detectives told them that Scarseth never met the couple, but was able to provide some helpful information Tuesday.
"It turned out to be a complete case of mistaken identity," Mark Scarseth, the man's father, said. "He is not the guy they were looking for."
They said they hadn't yet talked to their son themselves, and didn't know where he is headed. They also said they never thought he had anything to do with the crimes.
Sonoma County detectives sent out a statewide alert Tuesday seeking Scarseth as a "potential witness" in the killings. Scarseth contacted police after learning from media reports that he was being sought.
Sheriff's Lt. Dave Edmonds said Tuesday that Scarseth was being questioned but he was not in custody and was always free to go.
Karen Scarseth had said her son has an alcohol problem but is not violent. Court records show he has had various minor scrapes with the law.
"He's just roaming around," she said. "If he ran into those people (who were killed), he would have befriended them."
Mark Scarseth said the fact his son reported to police for questioning demonstrates what kind of person he is.
Karen Scarseth had said her son, who was raised Roman Catholic and attended Bible school, harbored anger toward religious people and sometimes "brings up religion and politics to irritate people. He likes to stir people up."
Still, Scarseth's mother said her son often relied on Christian charity to survive, and that he told her last week that he had gotten a hotel room in a small town through a voucher from a "church woman."