Police in Citrus County, Florida, say they’ve found more than 350,000 images and over 3,000 videos of child pornography on a computer belonging to a former music director at a local church.

Citrus County Sheriff’s Office said officers arrested Chad Everett Robison, 36, Thursday on charges including lewd and lascivious exhibition, and promoting the sexual performance of a child. Robison had served as the worship director at Seven Rivers Presbyterian Church in Lecanto between 2011 and mid-May, when detectives say they found the disturbing content on his computer.

One of Robison’s coworkers had made the discovery, according to the sheriff’s office. The worker had been trying to “prank” Robison, who had left his laptop at work, but he allegedly ended up stumbling upon the inappropriate images and videos instead, WPXI.com reported.

Seven Rivers Presbyterian Church, which a local reporter described as a “large church with a large congregation,” told WFTS-TV in a statement last week that it had dismissed Robison on May 15. The church alerted police after receiving “allegations about material” found on his personal laptop, it said. The church added it had banned Robison from its campus.

The sheriff’s office said at a press conference on Friday that detectives from its High-Tech Crimes unit had spent the past two months scouring Robison’s laptop for evidence. Sheriff Mike Prendergast said it took the team “hundreds of hours” to comb through the thousands of videos and images of child pornography found on the device. The content date back several years, said authorities, with some videos dating to “just a couple of months ago.”

“We have videos of Robison having virtual sex with an underage female who is not local, as well as trying to coerce young girls to show him their breasts while he masturbated on camera with them,” Prendergast said.

The sheriff described Robison as a “very sick man” and alleged the former music director had secretly videotaped young girls who’d used the bathroom in his home.

The victims were unaware that they were being recorded, said Prendergast, adding that the girls had yet to be identified and that additional charges against Robison “may be forthcoming.”

Detectives say Robison had used the free online chat website Omegle, among others, to meet his victims.

Captain Brian Spiddle said most of these victims have yet to be identified, though he said the children are “potentially from all over the United States and Canada.”

“We believe there could be multiple victims,” Spiddle said.

“It’s going to be a very difficult and long process to find those who have been victimized by this man.”

The sheriff’s office has urged parents, church parishioners and members of the public to come forward with any information they may have on the case.

Detective Chris Cornell, one of the officers tasked with sifting through the materials on Robison’s laptop, called the suspect a “textbook sexual predator.”

“This is the type of predator we warn kids about,” he said.