A South Carolina firing squad botched the execution of Mikal Mahdi last month, with shooters missing the target area on the man’s heart, causing him to suffer a prolonged death, according to autopsy records and his attorneys.

Mahdi, 42, was shot dead by corrections employees last month in the second firing squad execution this year in South Carolina. The state has aggressively revived capital punishment over the last seven months and brought back the controversial firearm method that has rarely been used in the modern death penalty era.

Autopsy documents and a photo reviewed by the Guardian, along with analysis commissioned by Mahdi’s lawyers, suggest the execution did not occur according to protocol, and that Mahdi endured pain beyond the “10-to-15 second” window of consciousness that was expected.