Capt. Anthony Marraccini said there was no mechanical or electrical failure in the car.
He said Monday that at the point of impact, the gas pedal was depressed all the way and there was no sign of any application of the brake.
The finding concurs with U.S. safety regulators who said last week that the car's onboard computers showed the throttle was open and the brakes were not applied.
A 56-year-old housekeeper driving the 2005 Prius in Harrison on March 9 reported that it sped up on its own down a driveway, despite her braking, and slammed into a stone wall. She was not seriously hurt.
The report came after a two-week investigation.
The accident set off an intense investigation. Toyota has recalled more than 8 million cars since the fall over gas pedals that could become stuck or be held down by floor mats.
Prius and other Toyota vehicles have been under examination by company, government and police investigators after a rash of reports of sudden acceleration.
A Nassau County woman who says she suffered serious injuries because her Toyota Prius refused to stop last year on the Wantagh Parkway is among a growing number suing the carmaker in connection with alleged incidents of "unintended acceleration."
Court papers and her attorney, Ted Trief of Manhattan, say she was driving home from work May 13 when her 2005 Prius was struck by another vehicle on the parkway. She tried to stop, but her vehicle continued to accelerate, the suit claims, causing her car to strike a third vehicle, leave the road and roll over three times. The suit also claims the car's air bags failed to properly deploy and her seat belt "improperly released.
This story was supplemented with a March 10, 2010 report from Newsday Staff Writer Tom Incantalupo.