A federal appeals court says Alabama's use of nitrogen gas for executions needs more study to see if it violates the constitutional ban on cruel and unusual punishment.

Add Yahoo as a preferred source to see more of our stories on Google. An inmate executed by Tennessee without deactivating his implanted defibrillator said he was hurting badly shortly after the lethal injection began, according to several witnesses.

Richard Djerf executed by lethal injection Richard Djerf was convicted of killing a Valley family of four in 1993. His execution was the second in Arizona this year. In March, Aaron Gunches was put to death.

Full coverage of the death penalty and capital punishment in the United States and breaking news about prison inmate executions and lethal injection protocols.