(Reuters) - Texas executed a Houston man on Thursday convicted in the 1988 killing of a teenager and her toddler cousin, a prison spokesman said.
Preston Hughes, 46, was convicted of stabbing to death 15-year-old Shandra Charles and her 3-year-old cousin, Marcell Taylor, in a vacant field near his apartment complex.
Hughes was executed at 7:52 p.m. Central Time. He was the 40th inmate executed in the United States this year and the 15th in Texas.
Hughes had maintained his innocence, first saying the deaths were an accident and then contending that he had nothing to do with them and that police had framed him. At the time, Hughes had been free on probation for the aggravated sexual assault of a 13-year-old girl.
In his final statement Thursday night, Hughes continued to maintain his innocence, according to a transcript provided by the Texas Department of Criminal Justice.
There was no DNA evidence linking him directly to the killings. Advocates and Hughes' lawyer insisted there were too many weaknesses in the case and that the evidence against him was either circumstantial or fabricated.
The 15-year-old girl and her cousin were found stabbed several times in the neck and chest, their jugular veins and aortas severed, according to an account by the Texas Attorney General's Office.
Authorities said Charles was still alive and told police that a man named Preston had stabbed her after trying to rape her. Critics of the case said Charles could not have stayed alive long enough to say anything to police.
Police found Hughes at his nearby apartment, along with a knife, some blood on his clothes, and Charles' eyeglasses on his couch, which Hughes later said were planted.
Hughes was convicted of capital murder by a Harris County jury during a trial in which the Houston police crime lab director was rebuked by the judge for waiting until he got into the courtroom to test a knife found in Hughes' apartment for blood - tests performed for the first time while jurors were waiting.
Shortly after, the Houston crime lab came under fire for shoddy practices, which led to the retesting of evidence in hundreds of cases.
(Reporting by Karen Brooks and James B. Kelleher; Editing by Cynthia Johnston and Eric Walsh)