Hossein Dabiri with Oklahoma Coalition Against the Death Penalty holds a sign protesting the death penalty at the State Capitol in Oklahoma City, Tuesday April 29, 2014. (AP Photo/The Oklahoman, Steve Gooch)

The director of the Oklahoma Department of Corrections revealed additional details Thursday regarding the botched execution of an inmate this week, while also recommending that all executions be delayed so the state can alter its execution protocols.

In a letter to Gov. Mary Fallin (R), Robert Patton laid out a timeline of what happened in the hours leading up to the bungled execution of Clayton Lockett on Tuesday night. Lockett, who was convicted of murder after he and accomplices had beaten and sexually assaulted two teenagers, died of a heart attack shortly after his execution went awry and was called off.

Patton’s timeline explains why the execution began later than the scheduled 6 p.m. start time. It took the technician who was attempting to insert the IV additional time because after examining Lockett’s arms, legs, feet and neck, the technician couldn’t find a place to insert the IV. Ultimately, the IV was inserted in Lockett’s groin area at 6:18 p.m., with a sheet placed over the area to keep witnesses from seeing his groin, Patton said.

The execution began at 6:23 p.m., which is when the blinds were lifted and witnesses were able to see into the execution chamber. At that point, Lockett declined to make a final statement and the officials began administering the drug midazolam, which is supposed to lead to unconsciousness.

At 6:33 p.m., Lockett was declared unconscious, which was announced to the witnesses in the adjoining room. At this point, vecuronium bromide (which stops respiration) and potassium chloride (which stops the heart) were both administered intravenously.

The timeline skips over what happens next, jumping ahead to when the blinds were lowered at 6:42 p.m. But witnesses who were in the room told the Washington Post that before the blinds were lowered, Lockett began grimacing, trying to lift his head and clenching his teeth.

At this point, the doctor examined the IV and saw that “the blood vein had collapsed, and the drugs had either absorbed into tissue, leaked out or both,” Patton said. (He said afterward that the line had “blown.”)

That was when the warden called Patton and told him what had happened. Patton was told that there hadn’t been enough drugs administered to kill Lockett and that there were no other veins available. He was also told that Lockett was unconscious and had a faint heartbeat. The execution was called off at 6:56 p.m. and Lockett was declared dead 10 minutes later.

In his letter, Patton said he believed the state’s execution protocols should be changed and asked for an indefinite stay of execution to allow time to alter the process and train staff members.

Patton also expressed support for an external investigation into the botched execution. Fallin announced an independent review on Wednesday and said that the execution of Charles Warner, which had been set to occur hours after Lockett’s, would be delayed until after the review was completed. Warner was convicted in 1999 of raping and murdering an 11-month old.