A former suburban Texas police officer has been executed for hiring two people to kill his estranged wife nearly 30 years ago.

Robert Fratta, 65, received a lethal injection at the state penitentiary in Huntsville for the November 1994 fatal shooting of his wife, Farah, in Houston.

He was pronounced dead at 7.49pm local time (1.49am GMT), 24 minutes after the lethal dose of the powerful sedative pentobarbital began flowing into his arms.

For about three minutes before the execution began, Fratta’s spiritual adviser, Barry Brown, prayed over Fratta, who was strapped to the death chamber gurney with intravenous needles in each arm.

Mr Brown, his prayer book on the pillow next to Fratta’s head and his right hand resting on Fratta’s right hand, asked for prayers for “hearts that have been broken … for people who grieved and those who will grieve in days ahead”.

He asked God to “be merciful to Bobby”.

Asked by the warden if he had a final statement, Fratta replied: “No.”

Mr Brown resumed praying as the lethal drugs began and Fratta, his eyes closed, took a deep breath and then snored loudly six times. Then all movement stopped.

Prosecutors say Fratta organised the murder plot during a contentious divorce and custody battle. A middleman, Joseph Prystash, hired the gunman, Howard Guidry.

Farah Fratta, 33, was shot twice in the head in her home’s garage in the Houston suburb of Atascocita.

Robert Fratta, who was a public safety officer for Missouri City, had long claimed he was innocent.

His punishment was delayed for little more than an hour until the last of a flurry of final-day appeals cleared the US supreme court and Texas’ highest courts, the Texas supreme court and Texas court of criminal Appeals.

Fratta’s lawyers argued unsuccessfully that prosecutors withheld evidence that a trial witness had been hypnotised by investigators, leading her to change her initial recollection that she saw two men at the murder scene as well as a getaway driver.

Prosecutors have argued the hypnosis produced no new information and no new identification. They had also said that Fratta had repeatedly expressed his desire to see his wife dead and asked several acquaintances if they knew anyone who would kill her, telling one friend: “I’ll just kill her, and I’ll do my time and when I get out, I’ll have my kids,” according to court records.

Prystash and Guidry were also sent to death row for the killing.

Fratta was first sentenced to death in 1996, but his conviction was overturned by a federal judge who ruled that confessions from his co-conspirators should not have been admitted into evidence.

In the same ruling, the judge wrote that “trial evidence showed Fratta to be egotistical, misogynistic, and vile, with a callous desire to kill his wife”.

He was retried and resentenced to death in 2009.