The crash happened early Sunday morning on the Bronx River Parkway. 32-year-old off-duty officer Kim Ho-Young was behind the wheel of his Nissan Altima when he lost control of the vehicle. The car slammed into a guardrail and rolled over on the parkway.
A toxicology report will determine whether officer Kim was drunk at the time of the crash.
Officer Kim reportedly was driving home from a party with another police officer, 25-year-old Edwin Paulino, and the four women crammed into his Altima.
Relatives of the women in the vehicle say Kim admitted to the women that he was quote, "a little tipsy," but insisted he was able to drive.
Jasmin Ramirez and Iris Gomez-Ramirez are listed in critical condition with broken bones and severe head injuries.
The two other women, identified as Melina Ramirez and Shirley Torres, are in serious condition.
Both officers were killed instantly. They worked together at the 32nd precinct in Harlem.