20 May 2009 :

A 51-year-old man was executed by lethal injection in Texas for the February 1986 murder of a young sales clerk as he robbed a convenience store.
In his last words Michael Lynn Riley apologized to the family of his victim. "I truly am sorry for the hurt and pain I caused you. I hope you can forgive me."
Riley was sentenced to death for the murder of Wynona Lynn Harris, a 23-year-old woman he stabbed 31 times as he robbed a convenience store on February 1, 1986 in the town of Quitman, east of Dallas, where she worked as a clerk.
Riley's first conviction and sentence were thrown out due to a jury-selection error, but he was again convicted in a second trial in September 1995 and sentenced to die.
Then in September 2005 a court of appeals granted Riley a stay of execution when lawyers argued that he was mentally challenged, as the US Supreme Court "has banned the execution of people who are mentally retarded," the Texas statement read.
He was determined to be mentally competent in September 2007, and after further court motions an execution date was set.
Riley is the 15th person executed since the start of 2009 in Texas, a state that has executed 438 inmates since 1976.