Kincaid drove up alongside the truck and both vehicles pulled over. He got out, announced he was a police officer and was reaching for his ID when an occupant of the truck shot him in the head. The 40-year-old off-duty sergeant died a few hours later.
Anthony Haynes, then 19, was arrested within days of the shooting in May 1998. In a confession recorded by detectives, Haynes said he was the driver of the pickup and that he shot Kincaid.
He was sentenced to death in September 1999. Haynes, now 33, is set for execution Thursday evening.
Prosecution evidence showed Haynes had an explosive temper and extreme mood swings likely fueled by drug use. Jurors were told how during an argument he held a gun to the head of his father, an arson investigator in Houston. Prosecutors also showed Haynes threatened people during an outburst at his high school nurse's office, that he assaulted his 3-year-old sister, tried to kill the family dog and used a shower curtain rod to attack a staff member at a hospital where he was being treated for explosive disorder and marijuana dependence.
Prosecutors said Haynes and his companions had been shooting at vehicles that night to get motorists to stop so they could rob them.
Defense attorneys argued that Haynes' trial lawyers didn't call sufficient witnesses testifying to his good character and in an appeal cited 39 people who were prepared to testify in Haynes' favor. The 5th U.S. Circuit Court of Appeals rejected that appeal earlier this week. Haynes' lawyers filed an appeal with the U.S. Supreme Court on Tuesday.
If it goes ahead, Haynes' execution will be the 11th this year in Texas. Five more are scheduled over the next month in the nation's most active capital punishment state.
Mark Vinson, a former Harris County assistant district attorney who prosecuted Haynes, described the young man as "no angel." Vinson said Haynes told investigators he wasn't aware Kincaid's wife, Nancy, had been in the car and if he had known he would have shot her too.
Police were led to Haynes after he threatened one of his friends who he thought might talk about the shooting.
"One of them became concerned and decided to go to authorities," Vinson said.
Ray Hunt, president of the Houston Police Officers Union, said Kincaid was one of his sergeants when he joined the force.
"Good friend, a great guy, good husband," Hunt said. "Just a tragic situation.
"He tried to stop some kids who had damaged some property and they senselessly take his life."
Haynes declined to speak to reporters from death row as his execution neared.