State police said the limousine in an upstate New York crash that killed 20 people failed to stop at an intersection.
Authorities said at a news conference Sunday that the 2001 Ford Excursion limousine plowed into an unoccupied sport-utility vehicle in a parking lot across from the intersection Saturday afternoon.
Two pedestrians there were also struck and died.
The other 18 victims in Saturday's crash were in the limousine.
Authorities say all the occupants died.
The crash was in Schoharie, about 270 kilometres north of New York City.
The aunt of one of the victims in the limo says the vehicle was on its way to a celebration.
Valerie Abeling said newlyweds Erin Vertucci and Shane McGowan were among those killed.
She said Vertucci was 34 and McGowan was 30.
Abeling added her daughter had been invited, along but was unable to go.
She also said "our lives have been changed forever.''
A witness said the crash "sounded like an explosion.''
Linda Riley of Schenectady, New York, said she was in a parked car at the Apple Barrel Country Store in Schoharie, when she heard the noise.
The store is a popular spot for autumn leaf-peepers.
She said she got out and saw a body on the ground by her vehicle, and broken tree branches everywhere.
The National Transportation Safety Board launched an investigation.
- With files from The Associated Press