DPA

An execution in the U.S. state of Ohio has drawn criticism after reports that it took 25 minutes for the lethal injection of a new mixture of chemicals to work.

The 53-year-old convicted murderer was put to death on Thursday at a state prison. Witnesses to the execution of Dennis McGuire described it as a gruesome death caused by the two-drug execution method that had never before been used by the U.S.

McGuire gasped for air and choked for more than 10 minutes, according to the Columbus Dispatch newspaper. He also struggled and made guttural noises before succumbing 24 minutes after the chemicals began to flow.

Allen Bohnert, one of McGuire’s lawyers, called the execution a “failed, agonizing experiment by the state of Ohio.” McGuire was convicted of killing Joy Stewart in 1989. He forced the pregnant 22-year-old from her car, attempted to rape her, sodomized her, choked and stabbed her. Her family issued a statement after the execution saying McGuire was treated “far more humanely” than he treated Stewart.

The two drugs used in the lethal injection were midazolam, a sedative, and hydromorphone, a morphine derivative, the state said.

The reason the new chemical mixture was used was because of a shortage of the chemical usually used in executions, pentobarbital.

There was no clear indication that the drug combination triggered McGuire’s death struggles. The Ohio Department of Rehabilitation and Correction had no comment on the execution.

U.S. states where the death penalty is legal previously bought the chemical from Europe, but countries there banned its export because of opposition to its use in executions.

A statewide organization to stop executions called for an immediate moratorium on executions after the “horrific events”.