We got a behind the scenes look at the crime lab and the science it uses to provide instrumental evidence in cases.
It was Dec. 11, 2017. Travis Clepper was driving in Magnolia when he crashed into another truck and was rushed to the hospital.
Meanwhile, Rhonda Melton was at home waiting for her husband Wayland to return.
"He was very involved with our congregation. In fact, that's where he was that night," Melton said.
Just before 9 p.m., the phone rang.
"I thought, 'There he is. He's calling me to tell me that he's running late,'" Melton said.
But it wasn't him. It was their daughter, telling her Wayland's truck had been hit. They later learned Clepper was the driver who hit him.
The crash was so bad it reduced Wayland's cab to almost half its size. Rhonda's partner of 47 years was gone in an instant.
"I just fell on the floor in the garage. I was just lying there in a heap. Literally, I felt like I couldn't breathe. I felt like I had just gone down to the valley of the shadow of death," she said.
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Troopers thought Clepper was drunk. He was also injured and he couldn't do a field sobriety test.
A test of his blood alcohol was all the more important.
"He couldn't walk. They had to pull him out of the car, those kind of things, the blood can be of utmost importance in being able to prove that someone is intoxicated and in being able to prove our case," said Andrew James, vehicular crimes chief at the Montgomery County District Attorney's Office.
The Department of Public Safety's crime lab does thousands of blood tests a year involving suspected DWIs like Clepper's.
The science involved in those tests is crucial to putting drunk drivers behind bars. Officers have special tubes in the field that are used in blood drawls.
Once they have the blood, it goes to the lab and into the hands of scientists who test the alcohol concentration. Forensic scientist Tifani Parker showed us the specialized machine they use to test the blood.
"This will tell us if there's alcohol in their system and if somebody says, 'I only had two drinks.' Usually with an alcohol concentration, we could probably determine how many drinks they had," Parker said.
Parker says in addition to a chemistry degree, she had six months of training before working in the lab.
Also, for crime scenes as complicated as drunk driving crashes, forensic scientists can test for DNA inside the car, like the steering wheel or the airbags to determine who was driving.
In Clepper's case, nearly three hours after the crash, his blood was still showing an alcohol level that was double the legal limit.
James says the blood sample proved instrumental in this case.
His life and the life of Rhonda Melton's changed forever.
"This has been devastating in my life," Melton said. "Everything in my life has changed."
Wayland died a day before Rhonda's birthday. She's reminded everyday of something he wrote in her Bible: "Do not give up."
Clepper is serving a 15-year sentence, all over a decision to drink and drive.