Austin — Former Texas Attorney General Jim Mattox, known as the junkyard dog of Texas politics who also served in Congress and battled Ann Richards in a vicious primary campaign for governor, has died.

He was 65.

Mattox, a bare-knuckled political brawler while the state was still fiercely Democratic, died at his Dripping Springs home, his sister, Janice Mattox, said Thursday. She did not know the cause of death.

Mattox was remembered for his advocacy of the everyday Texan, a reputation that earned him the nickname the "people's lawyer."

Chuck McDonald, a spokesman for Richards during the infamous 1990 Democratic primary, portrayed Mattox as a populist who knew how to fight.

"Jim was the original maverick. He prided himself on being the voice of the little guy and took on every big money interest group he could find," McDonald said. "As a political rival, he was as tough as they came. He never backed down from a fight and he made all the candidates stronger."

As attorney general, Mattox was head of the agency that fought efforts to spare condemned inmates from death. In late 1983, he showed up in Huntsville to be on hand for a midnight execution, the second lethal injection ever carried out in Texas.

An angry crowd threatened to get out of control when Mattox announced that the U.S. Supreme Court had ordered a delay. Security was tightened and the public was never again allowed to get near the doors of the prison in the hours preceding an execution.

Mattox continued to travel to Huntsville and was a fixture at executions in Texas, the nation's most active death penalty state.

Gov. Rick Perry ordered flags lowered to half-staff Thursday and Friday in honor of Mattox.

As attorney general, Mattox was known as a staunch advocate of Texas consumers whose battles often sparked controversy.

He sued Mobil Oil Co., an action that benefited a campaign donor. Mattox was indicted on commercial bribery charges but was acquitted by a jury in 1985.

He was elected to the U.S. House of Representatives in 1976 and remained in office until 1982. He was elected attorney general in 1982 and re-elected in 1986.

In his unsuccessful run for governor in 1990, his bruising campaign style — which some observers say alienated Democratic voters and cost him the nomination — was put on display.

He lost to Richards after accusing her of cocaine use with no evidence to back it up.

"Did she use marijuana? Or something worse, like cocaine? Not as a college kid, but as a 47-year-old elected official sworn to uphold the law," Mattox asked in one 1990 television ad.

Later he alleged outright that Richards, then the state treasurer, once was addicted to cocaine.

Glenn Smith, Richards' campaign manager in the 1990 race, described Mattox as relentless.

"He sure was a tough and vigorous opponent. Like he did everything, he gave it 150 or 200 percent. He was tough," Smith said.

To Mattox's credit, Smith said, once the Democratic primary against Richards was over, bitterness quickly faded.

"There was no ongoing antagonism," Smith said. "There was kind of a quick coming together afterward."

"We've lost a great Texan. I'm sad to hear it," he said.

That 1990 campaign effectively ended Mattox's political career, though he tried twice more, losing the Democratic primary for U.S. Senate in 1994 to Richard Fisher and losing another run at his old seat at the attorney general's office in 1998 to Republican John Cornyn.