Texas inmate Marvin Wilson was executed on Tuesday evening after the Supreme Court rejected an argument that Wilson should be exempt from the death penalty because he was mentally impaired.
Wilson was sentenced for killing police informant Jerry Williams in November 1992.
Lawyers argued that since a 2004 psychological test put Wilson's IQ at 61, the 54-year-old inmate was too mentally impaired to be executed. The generally accepted minimum IQ standard to face the death penalty is 70. According to the Associated Press, state attorneys countered that the argument of the defense was based on just one test and that other assessments indicated Wilson was not mentally impaired.
The United States is one of few countries worldwide to apply the death penalty. Data collected by Amnesty International in 2011 shows that only ten percent of countries in the world carried out the death penalty last year. According to the Associated Press, the U.S. was the only Western democracy to carry out the penalty in 2011.
Which countries have the worst execution records? Find out in the slideshow below. WARNING: Contains graphic content.