Video allegedly shows police using excessive force on pregnant woman in Brooklyn

Officers in Brooklyn are being accused of using excessive force on a pregnant woman. 
A new video posted on Facebook by a group called El Grito appears to show the police-involved fight in the borough's Sunset Park neighborhood early Saturday morning. 
The video allegedly shows cops struggling with and forcing down someone who appears to be pregnant. Another woman approaches and is apparently shoved by an officer. 
A spokesperson for the NYPD says the incident is being investigated by internal affairs. The department says that officers were trying to arrest a man for possession of a knife when several family members tried to intervene. 
That male suspect was eventually charged with criminal possession of a weapon. Two others were taken into custody, and charged with assault and resisting arrest. One woman was also given a summons for disorderly conduct.