EXCLUSIVE
Ex-NBA player Glen Rice Jr. allegedly beat up a former NCAA hoops player so badly, he broke the guy's jaw and knocked a tooth out ... this according to the police report, obtained by TMZ Sports.
We broke the story, Rice was arrested on July 25th in Georgia -- and according to the police report, one witness watched the violent scene unfold.
The witness told cops ... Rice and ex-Tulane player Jordan Callahan pulled into a Kroger parking lot in a white Porsche ... and got out of the car to have a conversation.
During the exchange, the witness says Rice clocked Callahan in the face -- knocking out the guy's tooth. The witness says Rice grabbed 2 bags from the car and ran down the street.
When cops arrived, they found Callahan in a pool of blood -- and the witness pointed to where Rice fled. Cops tracked down Rice and arrested him ... and found 2 bags nearby, hidden under leaves.
Inside the bags -- 2 guns (an AK-47 assault rifle and a Taurus .38 Special) and a bunch of bullets.
Cops say a 3rd gun was found in the Porsche.
There's more ... cops say Rice also had roughly $2,700 in cash and 6 cell phones on him at the time.
He was later charged with felony robbery, aggravated battery and marijuana possession.