UN human rights chief Volker Türk and nine independent experts have called on Tennessee not to make further attempts to execute Christa Pike.
The case
According to the UN, Ms Pike was twice injected with lethal drugs and survived. Mr Türk called the prolonged suffering abhorrent and cruel and raised questions about her trial.
Death penalty
The UN opposes capital punishment in all circumstances. The experts urged the state to commute her sentence. The UK abolished the death penalty for murder in 1965.
