D.O.C. Director Robert Patton said Lockett received his first injection at 6:23 p.m.
Seven minutes later, the other drugs were injected into his body.
However, Lockett maintained consciousness and witnesses say he began slowly convulsing.
Minutes later, a doctor in the room decided to stop the execution after a "vein line had blown" in Lockett, according to Patton.
At 7:06 p.m., 43 minutes after his first injection, Lockett suffered a heart attack and died inside the execution room.
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