The mother of a DWI-charged driver involved in a chain-reaction crash that ended with the driver’s friend being catapulted from a Queens overpass said a cop who slammed an EMT’s car, triggering the multicar collision, is to blame.

“The police officer caused the demolition and impact,” said Cecilia Maloney, mom of Samantha Maloney, 22.

Lt. Michael Silva, 38, has not been charged in Saturday’s tragedy. The NYPD’s Internal Affairs Bureau is investigating, police sources said.