Police are seeking help in identifying a man suspected of sexually assaulting a 22-year-old woman on a PATCO High Speed Line train in South Jersey early Sunday.

The suspect got out of a black pickup truck, possibly a Chevrolet, with black rims around 2 a.m. at the Westmont station, officials said.

The woman was attacked around 4 a.m. on a train somewhere between the Collingswood and Lindenwold stations, police said, adding that they would not release any additional information.

Investigators have released surveillance photos of the suspect and asked anyone with information to contact Camden County Prosecutor’s Office Detective Tanner Ogilvie at 856-650-6398 or Cpl. Joseph Ebling of the Delaware River Port Authority Police at 609-685-2521.

Philadelphia police, meanwhile, said they have arrested a suspect in the sexual assaults of three teenage girls and a woman, which occurred over less than two hours Tuesday morning in and near Center City.

Police said the groping incidents occurred in the Suburban Station concourse, a Broad Street Line station platform, at 16th and Vine Streets, and at Broad and Brown Streets, all between 6:45 a.m. and 8:35 a.m. Tuesday.

Erich Cunningham, 58, who is homeless, was arrested Wednesday in the same area where one of the attacks occurred, police said. He has been charged with unlawful contact with a child, indecent assault, simple assault, and harassment.