A suspected serial bank robber, identified as Joseph DiFalco, struck again Saturday morning at a Citibank branch on Cottman Avenue, law enforcement authorities said.

Officials believe DiFalco, 31, is the man who robbed a Wachovia Bank on South Broad Street on July 23, a Citizens Bank on Bustleton Avenue on July 26, and a Conestoga Bank on South Broad Street on Aug. 2.

On Saturday, the robber wore a brown baseball cap; a dark T-shirt with a long, gray shirt underneath; and jeans shorts, authorities said. No information about a weapon was released.

The FBI and Philadelphia police seek the public's help in finding DiFalco, described as white and 5-foot-5, with a thin to medium build, a thin beard, and tattoos on both forearms.

In previous thefts, the robber wore sunglasses and other baseball caps, including a Milwaukee Brewers cap. - Matt Katz