SAN ANTONIO -- Police arrested an elementary school principal accused of prolonged molestation of one of his students Tuesday afternoon.

Michael Alcoser, the principal at Carrilo Elementary in the South San Antonio Independent School District, was arrested without incident at an area hospital where he was being treated for an unknown medical condition.

Alcoser was charged with aggravated sexual assault.

The 41-year-old administrator was placed on administrative leave as the district investigated the student’s claims.

According to an affidavit released Tuesday, the 13-year-old student claimed the abuse began when he was 11 years old.

Officers said they recovered several pictures of the student as well as other pictures of unidentified children, according to the affidavit.

Police also said they discovered two pornography CDs that depicted adult men and adolescent males having sex, according to the affidavit.

“Generally speaking, as a rule, when we get a case like this, we look beyond the victim to see whether or not there are others,” San Antonio police Sgt. Gabe Trevino said.

Investigators are working with district officials to find out if other victims exist.