A 38-year-old convicted of murder of a teen woman 15 years ago died in what his lawyer called a “totally botched” death penalty execution in Oklahoma as he suffered in agony for 10 minutes, spurring officials to halt the process before he was felled by a fatal heart attack.

Clayton Lockett — whole sued the state with another condemned inmate (Charles Warner) after they became guinea pigs for a new tri-injection method officials were debuting, was seen in pain, clenching his teeth, groaning and writhing. State officials, seeing the pain, 86’ed the execution, the Department of Corrections said. By then it was too late, however, as his heart attack followed shortly thereafter.

"It was extremely difficult to watch,” Lockett’s lawyer David Autry said. "It was a horrible thing to witness. They should have anticipated possible problems with an untried execution protocol.