A man was executed Wednesday for initiating a murder-for-hire plot that authorities said led to the fatal stabbings of his parents and an uncle.

The lethal injection of Gregory Summers, 48, came more than seven years after the execution of Andrew Cantu, convicted of taking the $10,000 offer and fatally stabbing Gene and Helen Summers, both 64, and Billy Mack Summers, 60. Their home in Abilene was set on fire after they were attacked and their bodies were found in the rubble.

Asked by Warden Thomas Prasifka if he had a final statement, Summers replied "no." Eight minutes later, at 10:16 p.m. EDT, he was pronounced dead.

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Attorneys for Summers tried Wednesday to block the punishment by challenging the constitutionality of the lethal injection method, accusing prosecutors of hiding evidence and raising questions about testimony from a trial witness who implicated Summers.

The U.S. Supreme Court three weeks ago refused to review his case. Three appeals went to the high court late Wednesday, and all were rejected.

Authorities said the 1990 slayings were the result of Summers' parents' frustration with bailing their son out of his financial problems and Greg Summers' attempt to get $24,000 in life insurance.

"His father had come to the end of his rope with Greg and was starting to cut him off financially," said Kent Sutton, who prosecuted Summers. "Greg was going to inherit everything and that was one of the reasons he wanted the house burned."

Prosecutors also showed how Summers previously collected insurance payoffs from fires at his grandmother's house and a vehicle.

"Greg was pure evil. He'd been bleeding them dry for money over the years, and when he realized he couldn't get any more out of them, he figured he could get their insurance," said Miles LeBlanc, Sutton's prosecutor partner.

"He was so cruel in what he did to them and he needs to pay," said Brenda Steele, who lost her aunt and two uncles. "They loved Greg and they overlooked a lot of things they probably shouldn't have."

Cantu, 31, had denied involvement and blamed the killings on two companions who testified against him.

"We were able to find enough circumstantial evidence to piece together a strong case," LeBlanc said. "Greg Summers earned his conviction."

Summers was the 22nd inmate executed this year in Texas, the nation's most active death penalty state. At least three other inmates have execution dates over the next four weeks.

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