A self-proclaimed pedophilia advocate and accused kidnapper who was on trial for allegedly grooming a 12-year-old Fresno girl has died in custody in Arizona, according to public records.

Nathan Larson was arrested in 2020 by authorities who said they caught him flying across the country with the girl who he had persuaded to run away from home in Fresno.

Larson died Sept. 18 and an order of dismissal in his case was filed Oct. 11, the Sacramento Bee reported Monday. The U.S. Attorney’s Office had no further details on the death.

Arrested in Denver, Dies in Arizona

The Bee reported that Larson had been transferred from a federal facility in the Fresno area to a lockup in Arizona, where he died. The primary cause of death is pending, according to the medical examiner in Maricopa County, Arizona.

Larson, 41, last appeared in court in March, arguing to represent himself in a federal felony case that could have seen him serve life in prison if convicted, according to the Bee.

He was arrested in December 2020 at the Denver International Airport while attempting to take the girl to his home in Catlett, Virginia, where his plan was to sexually assault her and impregnate her when she turned 13, according to court records.

Larson made the girl wear a long-haired wig to make her look older and told her to pretend to be mute during their travel, Fresno County Sheriff Margaret Mims said at the time of his arrest.

Watch: News Conference on 2020 Arrest of Nathan Larson

Sheriff Mims Calls Larson a ‘White Supremacist, Advocate for Pedophilia’

Mims described Larson as a “white supremacist and a well-known advocate for pedophilia.”

Detectives said Larson met the girl through social media, flew to California, and persuaded her to sneak out of her house. A Denver police officer stopped the pair during a layover in Colorado. The girl was not injured and later was reunited with her family.