PHILADELPHIA (AP) — The bound bodies of two people were found in a Philadelphia river Wednesday, and a third man who said he managed to free himself was taken to a hospital for stab wounds, police said.

The bodies were found in the Schuylkill River in Fairmount Park just before 4 a.m. Wednesday, Chief Inspector Scott Small said.

"Both of the dead bodies had duct tape wrapped around their face. They also both appeared to be bound, their wrists and ankles. They also appeared to be tied or tethered to some piece of debris, some sort of weight used as an anchor to take them under water," he said.

Small said police were alerted to the presence of the bodies after finding a partially dressed 20-year-old man walking along the road with his wrists bound and duct tape around his face and ankles

"He was wet, and he told us he managed to get out of the river," Small said. He was taken to a hospital in stable condition with about nine stab wounds to his torso and both legs.

Small said the surviving victim reported that he was thrown into the back of a van in another part of Philadelphia by four or five people, and the other two victims were already in the van. Small said it was unclear whether the other two were alive or dead at the time. The man said he was robbed and stabbed before all three were tossed into the river, but he was able to free himself and climb out of the river.

"At this point, the only motive we have for the abduction and stabbing of our 20-year-old victim who's alive is robbery," Small said. "He claims when he was thrown in the back of the van and tied up and stabbed he was robbed of an undisclosed amount of money. He further states that the two other victims were already in the back of the van — he was not with the two other victims — so we don't know if the two other victims were related to the robbery."

Small said the other two victims were pronounced dead at the scene, and both remained unidentified.

"We're not even certain if they're males," he said, adding that police did not begin recovering the bodies until after daylight to allow investigation of the scene

Small said he would not disclose the place where the surviving victim was abducted, but police hoped to use surveillance video from that location to identify the van.