BOSTON (AP) — A teacher at a Massachusetts high school is facing child pornography charges after authorities acting on a tip say they found dozens of such images on his laptop, federal prosecutors said.

Thomas Davis, 41, a teacher at Foxborough High School, was charged Thursday with possession and receipt of child pornography, according to a statement from the U.S. attorney's office in Boston.

Authorities executed a search warrant at Davis' Mansfield residence on Thursday and performed an on-site examination of the device that revealed the images, some involving prepubescent children, prosecutors said.

According to an affidavit in the case, the investigation began after the FBI received a tip that Davis had shown someone a video allegedly depicting him having sex with a child. Davis denied that to investigators.

An email seeking comment was left with his federal public defender Friday.

Davis was detained following an initial court hearing Thursday pending a probable cause and detention hearing scheduled for Sept. 1.

Foxborough Superintendent Amy Berdos told WBZ-TV that Davis has been placed on unpaid administrative leave. According to the school’s website, Davis is a special education teacher.