By David DeKok

HARRISBURG, Pa. (Reuters) - None of the women in nude photographs posted on a Facebook page for a now-suspended Penn State fraternity is cooperating with investigators, police said on Friday, frustrating efforts to bring charges against the fraternity's members.

Earlier this week, Pennsylvania State University suspended the school's Kappa Delta Rho chapter for three years after discovering a private Facebook page that included photos of female students who were undressed, and in some cases, apparently unconscious or sleeping. The fraternity was also accused of hazing pledges and other objectionable conduct.

Prosecutors do not have a case against those responsible unless one of the victims is willing to go to court, Lieutenant Keith Robb of the State College Police Department told Reuters. Penn State is located in State College, Pennsylvania.

Robb would not say why the women declined to press charges, but said cooperating in a case can be difficult.

“You need courage to go to court," Robb said. "It’s not uncommon for victims to be reluctant to press charges, especially when it’s embarrassing, when there are nude photos involved.”

Penn State is still recovering from a child sex scandal in which a former assistant football coach, Jerry Sandusky, was convicted in 2012 of sexually abusing 10 boys over a 15-year period. The school's once-revered head football coach, Joe Paterno, and other Penn State officials were accused of covering up the abuse to protect the school's reputation.

Cases of racism, hazing, nude photos, vandalism and a death have rocked many U.S. college fraternities in recent months, including a University of Oklahoma chapter that was closed after a video surfaced in which students chanted about lynchings.

The Penn State fraternity brothers could face charges of invasion of privacy or harassment, Robb said. He added the statute of limitations on the alleged offenses runs until January 2017, two years after the Facebook page was reported to police.

Members of the suspended fraternity chapter have also declined to provide much cooperation, Robb said.

A spokeswoman for Penn State, Lisa Powers, said the university has on several occasions urged students to cooperate with the police investigation.Dalhousie University in Halifax, Nova Scotia, three months earlier was hit by a similar scandal, when a whistleblower revealed misogynistic jokes and messages posted on a private Facebook group by male dentistry students. The posts prompted a national outcry in Canada but there were no criminal prosecutions.

(Editing By Frank McGurty and Lisa Lambert)