A team in Oklahoma that prepared condemned murderer Clayton Lockett for execution in April failed to set a properly functioning I-V in his leg, according to preliminary findings of an independent autopsy released on Friday. The review was conducted by forensic pathologist Dr. Joseph Cohen in May and funded by Lockett's lawyers. Lockett's attempted execution occurred at the Oklahoma State Penitentiary in McAlester. He died from an apparent heart attack 43 minutes after the execution began. The autopsy was conducted separately from a formal state investigation. Outside examinations are common in certain cases. Documents: Not enough drugs left to finish botched Oklahoma execution . Oklahoma court grants stay after botched execution . Tennessee to use electric chair when lethal drugs unavailable . Appeals court stays Texas execution after intellectual disability claim .
Autopsy funded by inmates lawyer says IV improperly set . The lethal injection was botched and Clayton Lockett died 43 minutes later . The April fiasco in Oklahoma is under formal investigation .