Alix, 34, received lethal injection for the slaying of 23-year-old Eric Bridgeford, who interrupted Alix as he robbed the apartment of Bridgeford's sister. The sister also had been abducted and raped in what authorities said was part of a six-month series of crimes by Alix more than 11 years ago.
The execution was the fifth this year in Texas, the nation's busiest capital punishment state.
"I'm not the monster they painted me to be," Alix said from the death chamber gurney, saying he "messed up and made poor choices." He denied responsibility for several rapes and said he "did no drugs."
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"It is what it is," he said. "I've got peace in my heart."
Seven minutes later, at 6:20 p.m., he was pronounced dead.
Bridgeford's sister and her mother were among the people to watch Alix die. Others in the death chamber's witness area were the father and sister of Christopher Thomas, another man authorities said was killed by Alix the day after Bridgeford was slain. In all, authorities linked Alix to at least four killings.
Alix's lawyer, Robert Rosenberg, said court appeals to stop the execution were exhausted.
"Our lives are forever changed but we need to go on," Janey Bridgeford said after watching her son's killer die. "It was hard. I didn't take pleasure in that. I have forgiven him.
"I didn't think I'd get a verbal apology from him. I understood he may not come clean with everything."
"I killed the dude," Alix told The Associated Press recently from death row. "I wasn't trying to but I did. The dude wasn't bothering me. I was bothering him.
"I don't want to die. I'm remorseful. But I won't apologize."
But he did, to the Thomas family.
"I've been wanting to apologize to y'all for your son," he told them in the seconds before his death. "They told me not to do it in court."
"I have to accept it and I have to forgive in order for me to find peace within myself and a place in Heaven," Fernellifa Jolivette, Thomas' sister, said afterward. "If you don't, it will consume you. It will eat you alive ... In the end, he has God to answer to."
According to trial testimony, Alix abducted Bridgeford's sister Jan. 3, 1998, forced her into the trunk of a car, drove around and raped her, then brought her home. As he was ransacking her apartment, Bridgeford came in, saw Alix with a gun and ran off but was shot in the back. Alix fled and was arrested a few days later.
Alix denied the rape. He said he spotted the woman outside her apartment at night and considered her "easy prey."
He said he threatened to put her in the trunk of a car and she "volunteered to give me her TV" if he wouldn't kill her.
"That's how I got in her house," he said. "Her brother came home. It was just a simple robbery. My intention was never to kill anybody. I'm looking to rob, not kill."
He said he was behind a door when Bridgeford entered the apartment.
"I swung around, put the gun in his face," Alix said, "If I wanted to, I could have shot him between the eyes. I pushed off, and the gun went off. It happened in a second. It felt like hours. I looked at him and took off running."
Asked what he took in the robbery, he replied: "I didn't get nothing."
At his 1998 trial, his lawyers tried to convince the jury he didn't intend to kill Bridgeford. Jurors deliberated five hours before convicting him of capital murder.
Harris County prosecutors said Alix also was responsible for multiple rapes and robberies from August 1997 through January 1998. Alix said a debt of "a couple of thousand" dollars to a friend got out of control and forced him to turn to robbery.
"He was just a major-league crime spree," Luci Davidson, a former prosecutor now in private practice, recalled last week.
She said he confessed to most of the crimes. Alix said he confessed to the rape of Bridgeford's sister because he believed it would help him avoid the death penalty.
DNA evidence used in his trial also played a role in a scandal involving the Houston Police Department's crime lab when retests discredited the initial results.
But the 5th U.S. Circuit Court of Appeals, affirming a federal district judge's findings, said the DNA evidence was part of a "larger body of proof," including Alix's long history of violence, that showed jurors he was dangerous and should be sentenced to death.
Scheduled to die next, on April 22, is William Berkley, 31, condemned for the March 2000 abduction, robbery, rape and fatal shooting of 18-year-old Sophia Martinez, whose body was found outside El Paso.