The driver of a four-door sedan veered off Kelly Drive early Friday morning and crashed the car into the Schuylkill River, police said.

Rescue workers found the vehicle hours later, but have so far been unable to find any trace of the driver or passengers during their continued search in the water.

The car plunged into the river at about 3:45 a.m. on Kelly Drive near the Girard Avenue Bridge, police said. A witness told NBC10 he saw the car reverse at a high rate of speed, break a rope and plunge into the water.

The Philadelphia Police Marine Unit found the car about 25 to 30 feet under water shortly before 7:30 a.m., authorities said.

Police believe there was at least one person in the car when it plunged into the water — it’s unclear whether there were any passengers — but rescue workers have not yet located any of the vehicle’s occupants. Rescue efforts are still ongoing, police said.

The car’s plunge into the river was the second incident on or near Kelly Drive in less than 24 hours.

Just before 3:30 p.m. Thursday, a 41-year-old man was killed in a three-vehicle crash on the road near the Strawberry Mansion Bridge – less than half a mile from where the car drifted into the river, police said.

A black Nissan Altima was traveling south on Kelly Drive and attempted to make an illegal left turn at Reservoir Drive when a white Nissan Rogue struck the vehicle, causing it to spin and strike a black BMW, police said.

The Altima’s 41-year-old passenger, whose name was not released, was taken to Temple University Hospital, where he was pronounced dead at 4:02 p.m. Thursday, police said. The Altima’s driver, a 44-year-old man, was taken to Penn Presbyterian Medical Center, where he was listed in stable condition.

This is a developing story. Check back later for updates.