Guy Womack, Tippit's attorney, spoke with ABC13 reporter Daniela Hurtado on Thursday to discuss the matter.
Womack explained that Tippit was the only deputy on duty within the district that evening when he noticed a driver fishtail in front of him while he was parked in front of a school. That instance led to Tippit following Mendoza, who court records said accelerated up to 120 mph and ran several red lights before reaching his garage.
ORIGINAL REPORT: Chase suspect killed by Brazoria County deputy after attempted traffic stop, sheriff's office says
Records said that Tippit's body camera footage shows him approaching the driver's front door, pulling out the gun and firing.
"The deputy did not hear and didn't notice it in the height of the moment (and) didn't notice the sound of the weapon he was firing and didn't feel the recoil, but he was certainly holding the weapon," Womack told ABC13.
Womack says Tippit noticed the gunshot wound to Mendoza's arm, pulled him out of the car to place a tourniquet, but noticed that Mendoza couldn't breathe and began administering CPR.
The deputy's attorney said that the body camera and dashcam footage aligns with his claims and says this was an "accidental discharge," which is what Tippit is heard saying on the radios at the time of the shooting.
"What should not have happened was for the weapon to go off...and however that happened, that's the deepest tragedy in this case," Womack said.
SEE HERE: Former Brazoria Co. deputy charged with aggravated assault in teen's shooting death: Docs
Tippit was recently arrested and indicted on aggravated assault by a public servant charges by a grand jury two months following the shooting. He was fired shortly after, as BCSO said, due to "policy violations."
Mendoza's father released a statement that said in part: John Gabriel Mendoza Jr. was my son. His life mattered, and I will not allow his death to be minimized, excused, or forgotten.
Tippit faces five years up to life in prison if convicted.
Tune into the later editions of Eyewitness News for the full interview with reporter Daniela Hurtado.