Byron Black, a death row inmate with dementia and multiple organ failure, was executed by lethal injection despite having an active heart device his attorneys argued could cause extreme pain. Witnesses say he appeared to suffer during the procedure,

Byron Black, a death row inmate convicted of killing his girlfriend and her two young daughters, is scheduled to be executed this morning.

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