Dallas Cowboys Dez Bryant Reportedly Assaults Mother

The docs say ... cops were dispatched to Bryant's mother's home in DeSoto, Texas on July 14 at 1:47 PM after receiving a 911 call reporting an assault -- family violence.

Once cops arrived to the scene, Dez's mom Angela told cops she had gotten into an argument with Dez and demanded that he leave the home ... and that's when Dez got physical.

According to the documents, cops returned to Angela's home 2 days later and she complained of pain in her wrists, hands and arms .. and said her chest was sore from Dez pushing her.

Cops say they observed bruising in her upper arm. The docs list Dez Bryant as being 6'1", 198 pounds.