They wanted to know if any of them belong to 29-year-old Toni Lee Sharpless, a Chester County woman who has been missing for nearly three weeks.
"I know we want closure because just not knowing is very, very stressful, but at the same time, I really wish she was just okay somewhere," Toni Lee's sister Candy said.
Sharpless, of West Brandywine, was out partying with her friend, Crystal Johns, in the early morning hours of August 23.
Relatives and friends say Sharpless got into an argument at a house party in Penn Valley, took off alone in her black Grand Prix, and vanished.
Black Rock Park is near the location of the party.
"This the closest water location where a car could go into the water from where she was last seen; there's no particular indication she came down here, it's just a question we want to answer," Lt. Frank Higgins of the Lower Merion Police Department said.
Sharpless' last contact with anyone was a text message to her 12-year- old daughter, that same morning.
The girl is now staying with relatives, waiting for her mom to come home.
Dive teams took a look at several cars in the Schuylkill River, none of them belonged to Sharpless.
There are a few others they would like to take a look at.
They hope to resume their search sometime next week.