Marvin Wilson, 54, was executed by the State of Texas on Tuesday night.
A Texas man convicted of killing a police informant was executed Tuesday evening after the Supreme Court refused to hear arguments that he was mentally handicapped and therefore should not qualify for the death penalty, The Associated Press reported.
Marvin Wilson, 54, was pronounced dead at 6:27 p.m., 14 minutes after his lethal injection began at the state prison in Huntsville.
Wilson’s attorneys had challenged his execution as unconstitutional under the 2002 decision Atkins v. Virginia, which banned executing mentally retarded people but gave states some discretion in deciding who qualified for protection.
In their appeal to the high court, his attorneys pointed to a psychological test conducted in 2004 that pegged Wilson's IQ at 61, below the generally accepted minimum competency standard of 70. Federal law bans executions of mentally handicapped people as cruel and unusual punishment.
The defendant was convicted of murder for the November 1992 killing of a 21-year-old police drug informant, Jerry Robert Williams, and was sentenced to death in April 1994.
Lower courts agreed with state attorneys, who argued that Wilson's claim was based on a single test that may have been faulty and that his mental impairment claim isn't supported by other tests and assessments of him over the years.
The Supreme Court denied his request for a stay of execution less than two hours before his lethal injection began. Lead defense attorney Lee Kovarsky said he was "gravely disappointed and saddened" by the ruling, calling it "outrageous that the state of Texas continues to utilize unscientific guidelines ... to determine which citizens with intellectual disability are exempt from execution."
In Wilson's Supreme Court appeal, Kovarsky said Wilson's language and math skills "never progressed beyond an elementary school level," that he reads and writes below a second-grade level and that he was unable to manage his finances, pay bills or hold down a job.
Edward Marshall, a Texas assistant attorney general, said records show Wilson habitually gave less than full effort and "was manipulative and deceitful when it suited his interest," and that the state considered his ability to show personal independence and social responsibility in making its determinations.
"Considering Wilson's drug-dealing, street-gambler, criminal lifestyle since an early age, he was obviously competent at managing money, and not having a 9-to-5 job is no critical failure," Marshall said. "Wilson created schemes using a decoy to screen his thefts, hustled for jobs in the community, and orchestrated the execution of the snitch, demonstrating inventiveness, drive and leadership."
Wilson was the seventh person executed by lethal injection in Texas this year. At least nine other prisoners in the nation's most active death penalty state have execution dates in the coming months, including one later this month.
Reuters contributed to this report.
More content from NBCNews.com:
- Minister stands trial in international lesbian kidnap case
- Are nuns getting ready to spurn the Vatican?
- Girl, 6, found clinging to corpse in middle of lake
- Missing best friends found dead in New Jersey river
- Video: Athletes reveal the royal who makes them swoon