Officer Anthony Heims was arrested by the Dallas Police Department and charged with aggravated assault, according to a news release.Police responded to a 911 call from an Uber driver who reported his back seat passenger, identified as Heims, had pointed a pistol at his front seat passenger’s head while he was driving the two men, police said in the arrest warrant affidavit, obtained by CNN.The men then “struggled over the pistol, which discharged into the roof of the vehicle, damaging the sunroof,” the Uber driver said in the affidavit.A Glock 26, 9 mm pistol was recovered from the Uber, according to the affidavit.He didn’t remember “how he came to be in possession” of the pistol, but told police he had placed it on the front passenger seat after the gunshot, the affidavit said."