Mariano Gonzalez said he and his father stopped for a car that became disabled on the U.S. 59 off-ramp to Highway 288 at around 9:30 a.m.
According to Gonzalez, they saw a lot of blood around the vehicle.
Police said the driver of that vehicle and the driver of another vehicle had collided at some point on the freeway.
The driver of one of the cars, identified by police as Jorge Joya, pulled a gun and fired at the other car, according to police.
The gunshot victim, an 18-year-old, was hit in the face, investigators said. He was taken to Ben Taub Hospital, where he later died.
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Joya, 45, was charged aggravated assault in the shooting and was released from jail on a $30,000 bond. His passenger was not charged.
Gonzalez told Eyewitness News that as he tried to help, the victim had blood everywhere on his face.
"I proceeded to take off the seatbelt and see if I can help him. He was bleeding from his eye, everywhere from his face. And I had to drag him out so we can try to help him somehow. And when I did, I dragged him and somebody helped me straighten him out and put a pillow on (the) top of his head. It was quite a sight," Gonzalez recalled.
Gonzalez added that the driver of the other car, who was 200 to 300 feet away, did nothing to help
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