WASHINGTON — The US state of Missouri on Tuesday executed a man for the 2004 killing of his girlfriend and her three children, a crime that he denied until his death.

Leonard Taylor, 58, was pronounced dead at 6:16 pm local time (0016 GMT) after receiving a lethal injection in the Potosi penitentiary in the American Midwest.

Taylor was sentenced to death in 2008 for the murders of Angela Rowe and her three children, aged 10, six and five.

They were found dead, each with a bullet in the head, in their house on December 3, 2004. According to the forensic doctors, they had been dead for several days.

Taylor has always maintained that they were still alive on November 26, when he left the Jennings, Missouri home and flew to California.

At the trial, prosecutors said he confessed to the murders to his brother and that a witness saw him dispose of his gun. Jurors found him guilty.

Since then Taylor had made numerous attempts to clear his name — all unsuccessful.

Missouri Governor Mike Parson on Monday rejected his request for clemency.

“The evidence shows Taylor committed these atrocities and a jury found him guilty. Courts have consistently upheld Taylor’s convictions and sentences under the facts and the Missouri and United States Constitutions,” the Republican governor said in a statement.

The Innocence Project, which fights against miscarriages of justice and defends Taylor, claims that the brother’s testimony was obtained under duress and that he later recanted.

Taylor’s lawyers recently introduced the testimony of his daughter who swears her father was with her in California at the time of the murders, without succeeding in obtaining a reopening of the case.

They filed a final appeal Tuesday to the US Supreme Court, but it was denied.

Taylor was the fifth death row inmate executed since January 1 in the United States.