A Tennessee death row inmate's sister has filed a complaint against a doctor involved in his failed execution.

Florida has administered a lethal injection to a 74-year-old man, its oldest inmate in over a century, just weeks after executing another man who was briefly the oldest person executed by the state.

Florida is in the process of executing three of its oldest death row inmates back to back — each one older than the last.

Tennessee officials have called off the lethal injection of Tony Carruthers, who was convicted of kidnapping and murdering three people in 1994, after his executioners tried and failed for over an hour to establish an intravenous line.