A jail guard was shot and killed at a Pennsylvania courthouse by what appears to be friendly fire during a struggle with an inmate who had grabbed her weapon, and authorities said today they were investigating how it happened. The inmate had been taken from the Blair County jail to Central Court in Altoona for a hearing Wednesday when he disarmed corrections officer Rhonda Jean Russell, according to state police. Authorities said a law enforcement officer in the building opened fire on the inmate to stop him from harming Russell, who was struck by the bullet. The 47 year old Russell, of Altoona, was pronounced dead at UPMC Altoona, according to state police. State police did not identify the officer who opened fire, but Altoona Police Sgt. Matt Plummer said an Altoona police officer was involved.