Commissioner Raymond Kelly says the NYPD will look at a complaint that an officer wrongly used pepper spray at a demonstration last week.
Kelly says internal affairs will look into the claim made by a 25-year-old woman and others.
Video from Saturday's Union Square incident shows an officer blasting a cluster of women with pepper spray. Two of the women crumple on the sidewalk in pain. One screams. The officer's white shirt indicates a rank of lieutenant or above.
Kelly says the video leaves out tumultuous conduct by protesters who illegally tried to block streets.
About 80 people were arrested as the "Occupy Wall Street" demonstrators marched through lower Manhattan.
The women have also filed a complaint with the civilian complaint review board.