BELLEFONTE, Pa. — Prosecutors in Jerry Sandusky’s child sex abuse trial rested their case this morning after calling the mother of one of his alleged victims, who told the jury she thought it was unusual her son’s underwear was frequently missing from the laundry.

The woman also said the former Penn State assistant football coach contacted her son to be a character reference for him after the first round of charges were filed against him in November.

The woman said her son would claim he had thrown away his underwear because he had an accident. Last week, the teen said Sandusky forced him to have anal sex that made him bleed, but he’d “dealt with it.”

“I always wondered why he never had any underwear in the laundry,” she said. “There was never any underwear, any socks ... that was odd to me.”

The woman was the last of 21 witnesses presented by prosecutors in five days of testimony.

Sandusky’s attorneys immediately called their first witness, former Penn State assistant Dick Anderson.

Also Monday, prosecutors withdrew one count against Sandusky, saying the statute he was charged under did not apply at the time of the alleged illegal contact.

That leaves 51 counts involving 10 alleged victims over a 15-year span.

Sandusky, whose November arrest led to the ouster of Penn State’s president and the firing of Hall of Fame football coach Joe Paterno, has denied wrongdoing.