OGDEN -- The head of the Utah State Crime Lab says it would be almost impossible for a father's DNA to be confused with that of his son.
Jay Henry said lab policies prohibit him from commenting directly on his lab's DNA testing, which police say has tied Greg Seamons to the murder and rape of an 11-year-old Ogden girl in 1983.
So he couldn't speak directly about Seamons' claim in a letter to The Salt Lake Tribune that his late father likely committed the crime.
But speaking in general terms about DNA, Henry said, "Only one other person can have the exact same DNA as you, and that's a twin."
"I can't imagine that happening," he said of the possibility of a father's DNA being mistaken for the son's. "The word mix-up is not even applicable. It doesn't make sense."
He said he has never heard of a defendant, or a defense attorney, even attempting to make such a claim to explain away DNA evidence in a criminal case.
All individuals gain half their DNA code from the father and half from their mother, he said. A son's DNA would hold his mother's DNA, he said, but her strain would not be present in his father's genome.
Seamons has no defense attorney as officials wait on extradition proceedings to send him from the Idaho State Prison to Ogden's 2nd District Court.
In the letter, Seamons acknowledged "fooling around" with 11-year-old Rebecca Lemberger prior to her death in 1983, but he said he suspects his father likely killed the girl.
His father, Larry Bingham Seamons, died nearly a decade ago.
Lemberger, who lived in the same neighborhood, was last seen walking to school on March 2, 1983. Her body was found the next day in a shed in a field. She had been sexually assaulted, and she died from a blow to the head.
Seamons wrote that his father picked him and a neighborhood girl up one morning, and his father said he would drive him to school first and then drop her off at another school.
"I never saw this girl again and a few days later it came out on the news that she had been killed," he wrote in the letter.
Seamons is serving a sentence of four to 11 years for an unrelated 2007 second-degree kidnapping conviction in Ada County, Idaho. He is scheduled to be released in 2017.
Seamons remains in segregation at the Idaho prison because of the media attention his case has generated, he said in the letter.
"Lots of kids fool around sexually but that doesn't mean one kills the other," Seamons wrote. "I am innocent of this charge and angry that they plan to blame it on a 15-year-old boy."
Ogden Major Crimes Sgt. Tim Scott said this is the first time Seamons has pointed the finger at his deceased father, a move he described as "convenient," considering the elder Seamons is dead.
He said police would follow up any new leads, but he also said they are confident the right man has been charged with the rape and murder.
The girl's mother, Nola Mahon, said she doesn't remember Seamons or his father and doesn't believe either one ever visited their home. But she said she has confidence in the work performed by Ogden investigators.
"I think the DNA speaks for itself," she said. "Thank God for DNA."
In the letter, Seamons also claimed that his father molested him in the shower shortly after the girl died, but that he never told anyone until he was in his 30s. He said he suspects his father may have molested other youths.
According to Weber County court records from 1965, Larry Seamons was confined to a state mental hospital after he pleaded not guilty by reason of insanity to a charge of indecent assault on a 4-year-old girl when he was 21. Charging documents show he acknowledged that he and the girl had been naked together in a bed.
Psychiatrists determined that Larry Seamons was "legally sane" and had a passive-aggressive personality with some paranoid traits, according to court records. He subsequently pleaded guilty to taking "indecent liberties" with the child, completed probation and, as a result, the case was dismissed, court records showed.
Information from The Associated Press is included in this article.