State police are looking for the public's help in identifying a hit-and-run watercraft that struck another boat, injuring four occupants on Greenwood Lake on Monday.

Authorities said the reward for information leading to an arrest and conviction in connection with the case doubled on Wednesday to $10,000.

New Jersey State Police Sgt. Jeff Flynn says an unknown vessel, possibly a ski boat, struck the victims' 18-foot Bayliner boat. The boat's driver, Edwin Lane, 72, and a passenger, Robert Roon, 76, both suffered serious head injuries.

Two women, Mary Lane, 74, and Eileen Roon, 70, were also injured, but were able to render aid to their husbands and navigate the boat back to shore, according to Sgt. Flynn.

The two male victims were flown to St. Joseph's Hospital in Paterson and are listed in critical condition.

The two female victims were driven to the hospital by ambulance and had injuries that were not considered life-threatening.

State police have released a photograph of what the suspect's boat may have looked like.

Anyone who might have any information about the crash should call the state police Carteret Station at 732-541-0491.