Christa Pike is awake and speaking after surviving an execution attempt in Tennessee, her lawyers said Tuesday. The 50-year-old death row inmate remains in hospital receiving critical medical care, and her prognosis is unclear.

Pike survived two lethal injections last Wednesday. She was unconscious for days as medical staff cleared the injected chemical from her body. She was sentenced to death for murdering Colleen Slemmer with her then-boyfriend in 1995.

Fordham Law School criminologist Deborah Denno said seven other prisoners had survived execution attempts, but in those cases executioners had been unable to inject a substance into their veins. Authorities have not explained what went wrong after Pike was injected twice with pentobarbital, or said whether they will attempt another execution.