11:11 AM PT -- A spokesperson for the Virginia State Police tells us the agency has launched a criminal investigation into the incident. Once completed, the cops will submit the findings to the Isle of Wight Commonwealth Attorney for possible charges, or it could go to a special prosecutor.
At this point, it does not appear to be a federal investigation.
The traffic stop of an Army Lieutenant has now become a criminal investigation ... this according to the Lt.'s attorney.
Attorney Jonathan Arthur said on "TMZ Live" Monday ... he had been contacted by either the feds, state prosecutors or both regarding the December incident. He would not say which agency or agencies contacted him, but he did say a criminal investigation is afoot.
The feds could file criminal civil rights violations ... similar to what happened in the Rodney King case years ago. There could also be a state investigation over excessive force. As we reported, Lt. Caron Nazario was pepper-sprayed 4 times as officers barked orders at him.
Arthur filed a civil lawsuit earlier this month, and the video of the incident surfaced this weekend.
Attorney Arthur says the officers' conduct was egregious ... allegedly lying on the police report and also apparently telling Nazario if he doesn't complain they won't destroy his military career.
Arthur says his client has received solid support from higher-ups in the Army.