Authorities say the New Jersey police officer who lost his leg in a chain reaction accident Thursday afternoon may have lost control of his motorcycle before the crash.

Three motorcycle officers were escorting a funeral procession on Route 9W back to New Jersey when one of them slammed into a box truck.

The officer who was most seriously injured, Sgt. Bill Koretsky, remains in serious condition at Westchester Medical Center. He has been with the Bergen County Police Department for almost 25 years.

?The lead motorcycle, the Bergen County police officer, had a problem controlling the motorcycle,? says Det. Lt. John McAndrew of the Orangetown Police Department. ?For what reason? We don't know at this time.?

As a result of the accident, motorcycles were strewn across the road. Koretsky lost part of his left leg from the knee down. Another officer suffered a few broken ribs and was released from the hospital. The third had shoulder, arm and hand injuries, but nothing critical.

Investigators are still interviewing witnesses and waiting to speak to Koretsky himself.