A South Carolina man sent to death row twice for separate murders has been put to death by lethal injection in the state’s sixth execution in nine months.

South Carolina man Stephen Stanko died by lethal injection3. Stanko was convicted of killing his friend and girlfriend in April 2005, and also sexually assaulted his girlfriend's daughter.

Stephen Stanko was convicted of killing his live-in girlfriend as he raped her teenage daughter, then shooting a friend and cleaning out his bank account.

After he killed his 43-year-old girlfriend, Stanko then drove 25 miles north the Conway home of one of her friends, a 74-year-old man named Henry Lee Turner, a retired Air Force master sergeant and a father of three. He fatally shot Turner, whose body was found about 24 hours later, and stole his truck.

Lawyers for a South Carolina death row inmate are heading to federal court to argue that the state is not properly carrying out executions.