By Joe Holden

DARBY, Pa. (CBS) — Prosecutors in Delaware County have busted a Darby school security guard on charges of sexual assault of a student. They believe a pattern is developing, where the COVID-19 pandemic and school closures are driving an increase in predators seeking out children.

Hill would refer to her as “his wife and his girl,” according to court documents first obtained by CBS3.

Prosecutors say his control over her would only intensify.

“What we find in a lot of child predator cases are the individual puts a lot of time and effort into building that relationship of trust to get that child to do what the child knows in their heart is wrong,” said Delaware County District Attorney Jack Stollsteimer.

Court papers indicate the relationship became sexual when the accuser turned 14. At 16, she now worked at a local day care center where Hill was a camp counselor.

Detectives say he molested her on a trip back from the shore.

An affidavit claims he told the girl, “I kept my distance until it was time, when you were older, then I would feel comfortable enough to tell you how I feel.”

In July 2017, prosecutors say the two engaged in sexual intercourse inside the day care and even a school.

READ MORE: Delaware County Company Develops 'The Hurricane,' Device Using UVC Technology To Kill Coronavirus

“There is evidence that it took place in a school building, in the defendant’s home, and in a relative’s home of the defendant as well,” Stollsteimer said.

A spokeswoman for the William Penn School District said they are unaware of any incident involving Hill.

Hill’s lawyer declined to comment.

Online court documents show Hill was able to make bail, 10% of his $75,000 cash bond. He is due back in court in March.

Hill is the third man to be arrested on child sex charges in as many weeks. Delaware County has also busted Manuel Molina and Ivan Jackson Freeman.

A task force begun in September has seen an increase in complaints, in large part fueled by the pandemic.

MORE FROM CBSPHILLY.COM

Police: Teen Shot, Killed In Vacant Lot In West Philadelphia

Reports: Duce Staley Lands Coaching Job With Detroit Lions After Asking Philadelphia Eagles For Release

MORE NEWS: Fourth Bucks County Resident, Raechel Genco, Arrested For Alleged Role In Capitol Riot

Philadelphia Working To Find Other Partners To Administer COVID-19 Vaccines After Cutting Ties With Philly Fighting COVID