An Allegheny County Jail guard charged with sexually assaulting a female inmate was fired from his job yesterday after jail officials reviewed video surveillance footage that "corroborated the allegations," Warden Ramon Rustin said.

Charles L. Walker, 39, of Penn Hills, had been a guard at the jail since March 2004, the warden said.

Mr. Walker was charged Thursday with institutional sexual assault, aggravated indecent assault, sex assault and indecent assault after the inmate told county police he forced her to touch him sexually and to perform a sex act on him last month.

Through footage from video cameras in the inmate's housing unit, "we actually verified that something happened," Mr. Rustin said. Officials terminated Mr. Walker based on an internal investigation, which included consideration of the footage and the arrest report.

It was the first arrest of a jail guard on sexual assault charges in at least five years and prompted a review of jail protocols, particularly pertaining to communication throughout the facility, Mr. Rustin said. Officials want to learn how incidents and inmate complaints are conveyed to them and whether that communication system is effective, among other concerns.

"We've got a really good system that allows us to quickly qet rid of bad officers, but there's always room for improvement," Mr. Rustin said. "We take incidents like this and use them as opportunities to perfect our system."

Chuck Mandarino, a corrections officer and president of the Allegheny County Prison Employees Independent Union, could not be reached for comment.

The inmate, in jail since Feb. 25, told detectives that several times on Dec. 27, Mr. Walker grabbed her hand and forced her to touch his genitals through his clothes and, at one point, put his hand down her pants, exposed himself and forced her to perform a sex act on him, according to the complaint.

Mr. Walker denied some of the woman's statements when questioned by police, the complaint says, and he told police the inmate initiated the sexual contact.

The Post-Gazette does not identify alleged victims of sexual assault.

"The situation is horrific," said Stephen Misko, an attorney who represents the inmate. "I hope to God it's isolated and not widespread."

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