Gregg Page, 34, is charged with murder and attempted murder. Brothers 30-year-old Ryan and 27-year-old Ramir Schenck are charged with hindering apprehension.
Investigators say Page fatally shot 32-year-old Carley Elbert.
She had just gone into remission from a chronic illness.
Page is also accused of wounding 29-year-old Kamille Stewart.
Both women found shot in the head on a jetty behind the Flagship Resort at Main and the Boardwalk on August 1.
When police responded, Stewart was conscious but appeared to have multiple wounds. However, Elbert was unresponsive and pronounced dead at the scene. She was said to be wearing a bathing suit at the time.
Security at the Flagship resort turned over their surveillance video to police.
They told Action News at the time that the video showed a car pulling up just after 2 a.m., with five people getting out. They walk the boardwalk. About 20 minutes later, the video reportedly shows just two men returning before getting in the car and driving off.
According to a criminal complaint obtained by Action News, Page fled in a car belonging to one of the victims. He was allegedly seen on video driving the car and discarding it at another location. He was then reportedly picked up by his co-conspirators and fled in another car to Philadelphia, said investigators.
Elbert's mother helped lead police to the alleged killer after a ping to her phone tracked it to the 6100 block of Mulberry Street in Northeast Philadelphia, where police captured the suspects.
Exclusive video shows officers, including the FBI, arresting the three men.