ATMORE, Ala. (AP) — A man who killed his former girlfriend with a shotgun in 1993 while she slept was executed Thursday evening, his death witnessed by two of his sisters who cried, screamed and prayed loudly in a nearby room.

Prison officials said Holly Wood, 50, died by injection at 6:21 p.m. at Holman Prison in Atmore, becoming the fourth inmate to be executed in Alabama this year. He had no last words.

The sisters, Johnnie Pearl Wood and Mae Ole Wood Herndon, at one point knocked on the glass separating the witness room and the execution chamber and shoved aside some of the chairs in their room. The commotion peaked just as Wood’s head fell backward and he appeared to lose consciousness.

Wood never seemed to acknowledge that he saw or heard what was going on in the witness room about 10 feet away.

Authorities say Wood broke into the Troy home of his former girlfriend in 1993 and shot the sleeping woman, 34-year-old Ruby Gosha, in the head.

His attorneys claimed he had an IQ of 70 or less and that his trial lawyers wrongly failed to tell the jury about his mental limitations. Prosecutors said he was not as mentally disabled as claimed.

Wood lost last-minute pleas to Alabama Gov. Bob Riley and to the U.S. Supreme Court Thursday.

After leaving the witness room, the sisters left a handwritten note with corrections officers for The Associated Press saying their brother was mentally disabled and that Riley should have stopped the execution.

“The law failed to protect the mentally disabled. … The legal system in Alabama is flawed,” the note said.

Riley had issued a statement earlier after rejecting a clemency plea.

“For his brutal crime, he was tried and convicted by a jury and the jury recommended he be sentenced to death. This conviction and death sentence have been upheld by higher courts and I see no reason why this office should overturn the sentence,” Riley said in the statement.

Wood was the fourth person executed in Alabama this year and the 10th in the last two years. The state resumed executions in 1983 after a court-ordered moratorium.

The clemency petition said state psychiatrists have said Wood is mentally disabled and that his reading, spelling and arithmetic skills are in the second- to fourth-grade range. The petition had asked Riley to stop the execution partly because his attorneys failed to tell jurors that he was mentally disabled in the sentencing phase of trial.

The Alabama Attorney General’s Office filed a brief asking the Supreme Court to allow Wood’s execution to proceed, arguing that Wood has been on death row for 16 years and that his claims have been considered previously by federal and state courts.

The attorney general’s office also said that before his arrest, Wood held several jobs and was able to function in society. It also argued that Wood showed mental acuity in the way he planned and carried out the killing of Gosha.

Two of Gosha’s children, Willie and Latisha Goshe, witnessed the execution in a separate room from Wood’s sisters and declined to be interviewed.