GERMANTOWN (WPVI) -- Police are investigating the fatal shooting of a robbery suspect by an off-duty Philadelphia Housing Authority officer.The incident happened around 6:45 p.m. Sunday in the 400 block of West School House Lane.Police said the off-duty officer was walking westbound when he was approached by two males, at least one of which was armed.When the men attempted to rob the officer, he fired 7 shots, striking one suspect several times, police said.The wounded suspect was taken to Temple University Hospital where he was later pronounced dead.The second suspect got away.The PHA officer was not injured.