expedition. no one really knows. but we did see investigators uncover two corroded rifles from the car. investigators say they have not ruled out foul play yet, but they suspect that these six victims accidentally drowned, that the cars rolled back into the water and the victims were trapped inside. the cars were discovered by a team of divers with the oklahoma highway patrol. darrel spawn and his colleagues were testing new sonar equipment. >> you can't see anything the it's too murky. >> reporter: it wasn't until the cars were pulled out of the water that the gruesome and mysterious discovery was made. >> could have been a shoe. but then whenever we brought them up onto the shore, that was whenever the doors opened and you could see the skeletal remains in them. >> reporter: that's your grandfather right there? >> john alba porter is believed to be one of the victims in the second car. he and two friend were last seen driving a 1950s chevy when they disappeared in 1969, a year before the teenagers went missing this.