Scott Hancock allegedly admitted to sexually abusing 13 to 14 children before he turned 18.
The abuse took place in four different states over the course of years, say officials.
After serving a four-year sentence for his crimes in Utah and Oregon, Hancock, 21, is in Franklin County jail accused of molesting four children between 2016 and 2017.
Hancock faces four counts of first-degree child molestation and one count of first-degree child rape. He is being held in lieu of $250,000 bail.
An investigation into Hancock's string of abuse started in January when one of his alleged victims was caught molesting another child, according to court documents.
It's believed Hancock groomed the child starting when the boy was only 5, according to court documents. The abuse allegedly happened in Oregon, California and Utah, as well as Pasco.
He also forced that child to rape other children.
Police believe the last time he abused the child was in 2018 when Hancock was 15.
He also allegedly abused three other young children in a Pasco home.
He was arrested in Utah after he left one young child severely scarred and allegedly molested three other children.
When police interviewed him in 2019, he allegedly admitted to inappropriately touching about 14 children, according to court documents. He didn't provide any other details about the other abuse. Hancock was 17 at the time.
He was convicted of sex crimes in Utah and then later in Oregon. He was released on those charges in May 2023, according to court documents.