Two teenage cousins jumped into the murky Delaware River last night to save an 18-year-old girl who fell in - but only one of the would-be rescuers resurfaced.

Josh Garner, 19, and William Wilkinson, 17, jumped into the 65-degree water to rescue Jennifer Torres, 18, according to police Chief Inspector Scott Small.

Garner was able to rescue Torres, but Wilkinson never resurfaced. Garner and Torres were treated by medics on the scene but were not hospitalized, Small said.

About 6:30 p.m., police said, the three teens were hanging out behind a vacant property on State Road near Linden Avenue, near Pennypack Park, when Torres fell in.

By 10 p.m. the effort to rescue Wilkinson became a recovery mission, with marine units from multiple agencies using sonar equipment and manually dragging the river to try to find his body. The search was called off for the night at 11.

Boats from the Police Department, the Fire Department, the Coast Guard and New Jersey State Police were dispatched to the area.

Small said that although the teens weren't swimming, the Delaware River is extremely dangerous. "The current is very strong; there's an undertow," he said, "There's also no visibility."

Small added that the river's current carries debris that could hit or impale someone who falls in.