2:25 PM PT -- Cops say they found a semi-automatic pistol in the front passenger seat of Pryor's Mercedes-Benz ... along with a TON of blood inside the vehicle.
There's more, WPXI's Amy Hudak says cops also recovered a Glock pistol with a flashlight.
Hudak also reports a witness at the hospital was overheard saying, "We should have just let him die." Hudak says witnesses told police the two had a "very volatile relationship": and that Pryor "always had his hands all over her."
1:59 PM PT -- Terrelle Pryor has been arrested and charged with simple assault, according to the Pittsburgh Police.