After 15 years of failed appeals, convicted killer Brett Hartmann was strapped to a gurney Tuesday morning at the Southern Ohio Correctional Facility. “I’m good. Let’s roll,” he said in his final words as a dose of lethal drugs were shot into his system, reports the Akron Beacon Journal. He smiled and gave a thumbs up to his sister as she watched the execution through a glass window. Sixteen minutes later, he was declared dead.

He maintained his innocence since his 1997 conviction for the slaying and mutilation of Winda Snipes, 46, of Akron. In a statement released after the execution, Hartmann’s family, which includes a daughter and sister, said they hope the death serves as a “wake up call to the flaws in our legal system.” Prosecutors have always said there was “overwhelming” evidence of his guilt. In a 25-minute phone call Monday night with a Beacon Journal reporter, Hartmann, 38, said, “It’s the road I got to walk,” he said. “It’s my time. It’s hard, especially for my family. But it’s not overwhelming for me. I’ve just never had any luck.”