One detective said that the human race hasn't invented words yet to describe what they found in the trailer of 57-year-old William Charles Thomas.
He lives in the Midway Village Trailer Park in Morrisville, Pennsylvania. Investigators released multiple photos of him dating back almost a decade in hopes of helping victims identify him.
Police say Thomas is an independent contractor who is charged with the sexual assault of as many as six children, including a relative, over the last 40 years.
According to investigators, he inadvertently left evidence behind in his old trailer that was found while it was being rehabbed.
That evidence, police say, included a vivid description of an assault.
District Attorney Matt Weintraub said a search revealed more than 1,000 pieces of child porn and 1,000 pairs of soiled little girl's underwear.
VIDEO: D.A. Matt Weintraub
"And these pairs of underwear were displayed almost throughout his mobile trailer home," said Weintraub.
"This was a perverse shrine to his criminal conquests, and we are merely scratching the surface of those conquests today," Weintraub continued. "To be blunt about it, this is a real life boogeyman."
"Try to come up with your worst scenario and times that by 10, and you'll get close to what we saw. It was horrific," said Lt. Henry Ward of the Falls Twp. Police Department.
VIDEO: Lt. Henry Ward
Investigators say Thomas was a "monumental" trophy collector, and there fear is there may be more victims.
Police want anyone who may have hired him, operating under the business name of Thomas Construction, to contact the D.A.'s office or Falls Twp. police.
The fear is he would steal young girl's underwear while working in other people's homes.
Thomas could face life in prison.
Falls Township Seargeant Christopher Clark at 215-302-3315 or firstname.lastname@example.org
Bucks County Detective Lt. Robert Gorman at 215-340-8141 or email@example.com