We're not showing the video in its entirety, which was posted online, because it's too graphic.
The video shows a pickup truck go airborne and cross the center median before crashing into the top of an oncoming vehicle.
Sources say 54-year-old Charles Glaze was behind the wheel when he crossed from the westbound lanes of Highway 99, over the median and into oncoming traffic, striking four vehicles.
The crash left twisted metal and shattered glass across all lanes of the road.
Several vehicles were left mangled or torn to pieces. A boat on a trailer was seen in the middle of the wreckage.
Glaze's truck overturned. Katy police officer Johnny Alvarez helped pull Glaze out of his rolled over Ford F-150.
"I got on my knees and I entered the vehicle through the rear passenger window. We were applying first aid and we just assisted him in any way we could," Alvarez said.
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Glaze reportedly told authorities he didn't know what happened before the crash.
Deputies said he did not appear to be intoxicated and that he is cooperating with their investigation. He has not been charged in the crash.
Authorities tell ABC13 Glaze also had a history of seizures, but it wasn't immediately known if he was cleared by a doctor to drive.
Michael Brown was one of the victims who was killed. He was driving a silver Chevy crossover.
Neighbors described him as loving, compassionate man and grandfather figure to everyone in their area.
"He was a generous, sweet man. He would sit in his garage and make sure the kids in the neighborhood were safe. He would always wave at us and say hello, talk to us at the mailbox. He was a really great man," said neighbor Jackie Gandy.
A woman driving a Lexus also died. She has been identified by her son as Linda Fuggiti.
Fuggiti's son was out of the country when he learned of his mother's death. He says she was an amazing mother.
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