Local and federal law enforcement agencies searched the elementary, middle and high school buildings in Petersburg for about five hours Saturday. That’s according to school superintendent Rob Thomason who says a member of the staff who is the subject of the investigation resigned Tuesday.

In a letter sent to parents Tuesday, school superintendent Rob Thomason writes “serious allegations of possession of inappropriate photographs of children have been made regarding a school district employee.”

The school district is not naming the staff member and Thomason says they’re cooperating with authorities. Joe Viechnicki spoke with Thomason Tuesday.

Thomason’s letter to parents says because of content filters and monitoring of network traffic the district believes no downloading of photographs or inappropriate material took place at the schools, during work hours or using district computer equipment.

The Federal Bureau of Investigation’s Eric Gonzalez Monday declined to provide any information other than to say the agency executed a search warrant in Petersburg as part of an ongoing investigation. Gonzales said Monday no one has been arrested by the FBI and no charges have been filed.