George Whitaker, who was convicted of killing the sister of a former girlfriend, was executed by lethal injection in Texas, authorities said.
"He was pronounced deceased at 6:15 pm," Wednesday, a prison spokesman said.
On June 15, 1994, Whitaker, then 23, entered the home of his former girlfriend, Catina, two months after they had parted ways. He shot her mother twice, beat her five-year-old sister and shot dead her sister Shakeitha, 17, with a bullet to the head.
A defense attorney, former judge Jay Burnett, argued that Whitaker deserved a new trial because the judge in his initial trial did not tell the jury Whitaker could not be released on parole until he had served 40 years in prison. He lost his appeal bid however.
Whitaker is the 16th death row inmate executed this year in Texas, and the 420th since the US state resumed capital punishment in 1974.
Four more inmates on death row in Texas are scheduled to be executed by November 20.
