After the execution of Byron Black on Aug. 5, witnesses are slated to speak at a news conference outside the prison.

Tennessee executed death row inmate Byron Black on Tuesday despite raised concerns about his implanted heart device, which could cause a "prolonged and torturous execution."

Tennessee death row inmate Byron Black moaned and said he was in pain during his execution, according to reporters who witnessed the lethal injection Tuesday morning. Black's attorney said his distress was evidence he was "tortured.