Update: State police have identified the person killed Thursday in a one vehicle crash in the town of Theresa.

Investigators said 23 year old Thomas Uzailko of Theresa suffered fatal injuries when he was thrown from the back of the pickup where he and another passenger were riding. 

Uzailko died at Samaritan Medical Center in Watertown, police said.

Police said the driver, 21 year old Robert Galey of Theresa, told them the back tires of the pickup locked up - sending the truck into a ditch and a culvert before it overturned.

Investigators said Galey was not injured.

The second passenger in the bed of the truck, 20 year old Shanna Knight of Antwerp, was airlifted to Upstate University Medical Center in Syracuse with serious injuries. 

According to police, the vehicle landed on top of Knight.

She was in critical condition Friday afternoon.

The passenger in the cab of the pickup was identified as 16 year old Zachary Chambers of Theresa.

Chambers was taken to Samaritan Medical Center for treatment, but SMC said he was later transferred to Upstate University Medical Center in Syracuse.

His condition was not available.

Investigators said there's no indication that drugs or alcohol were involved.

The accident happened along Route 21 in Theresa in northern Jefferson County shortly after 3 p.m.

What follows is our earlier report:

A young man was killed Thursday afternoon when the pickup truck he was riding in flipped over, according to a relative of one of the people involved in the crash.

It happened along Route 21 in Theresa in northern Jefferson County shortly after 3 p.m.

A woman on the scene, Krystin Chambers, identified herself as a relative of a person involved in the accident.

She told 7 News reporter Asa Stackel that four people were involved and that one person, a young man, was killed. 7 News was given names, but we are withholding them until next of kin are notified.

She said two other passengers in the vehicle were injured.

A state police investigator said all of the people injured in the accident were alive when they were taken from the accident scene.

The accident happened when a red pick up truck flipped near a house and a barn on the rural, winding road.

The investigator said a female and a male were in the bed of the pickup truck; they were the most seriously injured.

The female was airlifted to Syracuse. The male was reportedly the person killed.

Two males were in the cab. One was taken to Samaritan Medical Center; the other, the driver, was apparently not injured.

State police released little information about the incident through Thursday evening, and reporters were kept back from the scene for two hours Thursday afternoon.