PHILADELPHIA (KYW Newsradio) — Philadelphia police are investigating a bizarre discovery: They say a fisherman found part of a human leg in the Delaware River.

Detectives say a 27-year-old man was fishing near Graffiti Pier at Delaware Avenue and Beach Street, when he came across the remains Thursday around 8 p.m.

The lower part of a right leg, from the kneecap to the foot, still had a sneaker on it.

Police do not know who the leg may have belonged to, or how it got into the river. Investigators are searching for any additional remains.