9:06 AM PT -- Yonkers PD has released body cam footage of the incident, and tells TMZ Hip Hop ... the woman was arrested for reckless driving of an unregistered moped.
As for the way she was taken down -- they claim she was fleeing, and when officers caught up ... "The individual continued to refuse to comply, at which time an Officer utilized a standard take-down to bring her to the ground to be handcuffed."
The Dept. says it immediately opened a use-of-force investigation, even before the Styles P video was posted on social media, and ... "The early stages of this investigation reveal that no strikes were used at any time during the incident and no force was used after handcuffs were applied."
LOX rapper Styles P intervened while cops arrested a woman, accusing them of roughing her up outside the NY juice bar he owns with Jadakiss ... and the whole thing's on video!!!
The video starts right in front of Juices For Life, just as a couple of Yonkers Police officers slam a woman to the ground and try to handcuff her.
The officers scream the woman is under arrest, but never specify why ... and that's when Styles P runs into the shot screaming at them. He tells another bystander to keep recording as he gets right up in the face of one of the cops, and yells about their aggressive tactics.
The woman recording claims the cops have been targeting women. Styles then challenges the officers, saying they were scared of Black people and were unfamiliar with the area.
At one point it seemed like they were gonna arrest Styles, but that didn't happen.
After cooling down a bit, Styles jumped on IG, and admitted he was wrong for his hostility towards the officer ... but admits seeing a woman involved in the ruckus made him act "out of character."