You and your girlfriend need to consult with a local criminal attorney immediately. Do not delay. Save all text and voice messages.
I am a co-author of WEITZ ON AUTOMOBILE LITIGATION: THE NO FAULT HANDBOOK. The opinions expressed in this answer are not intended to be taken as legal advice. These opinions are based on New York practice. I may be contacted at 212-553-9300.
I suggest that you contact a criminal defense attorney to address these issues. You have provided only your version of events, not that I doubt them , it is just one side and bith are needed. .With the attorney you can discuss filing a complaint with the cops agency's internal affairs unit as well as whether or not there is a civil suit against the cops.
The above is not intended as legal advice. The response does not constitute the creation of an attorney client relationship as this forum does not provide for a confidential communication.