(CNN) The execution of Arkansas death row inmate Kenneth Williams is raising questions after witnesses reports say his body repeatedly lurched when a lethal drug coursed through his veins.

Williams, 38, was the last of four Arkansas inmates put to death in eight days.

On Friday, Williams' attorneys called for an investigation into the "problematic" execution. But state officials said he showed no pain.

Here's a rundown of the last hours leading to and during Williams execution Thursday night as told by state authorities and media witnesses. All times local.

3:11 p.m.: Last meal

After taking communion, dinner was served in Williams' cell.

He ate two pieces of fried chicken with a side of sweet rice, BBQ pinto beans and one slice of bread. For dessert, he had one peanut butter cookie and a cinnamon roll.

10:19 p.m.: Williams leaves his cell

He was escorted from a quiet cell in the Arkansas' Cummins Unit prison to the execution chamber.

At the chamber, guards spent eight minutes restraining Williams to a gurney.

Then, members of the execution team placed a catheter and two intravenous lines in his body in 17 minutes.

10:29 p.m.: Witnesses arrive

A total of 31 witnesses walked into the chamber's viewing room to watch Williams' execution.

Several family members of the victims, Arkansas state Sen. Trent Garner and a "spiritual adviser" were among the witnesses.

Jodie Efird, daughter of victim Cecil Boren, watched the execution. She said Williams' death may not bring closure to her family , but it helps a little.

"Every time we drive down this road, he's not here anymore," she said of Williams.

Once everyone made it inside, all doors in the viewing room and death chamber were locked four minutes later.

10:50 p.m.: Last words

Witnesses saw Williams for the first time restrained to the gurney as a black curtain was opened.

Wendy Kelley, director of the Arkansas Department of Correction, gave Williams a last opportunity to speak before the execution.

He read the following prepared statement from a sheet of paper that Kelley was holding for him:

"I humbly extend my sincerest of apologies to the families I senselessly wronged and deprived of their loved ones. The families of: Dominique Hurd, Jerell Jenkins, Cecil Boren, Michael Greenwood.

I was more than wrong. The crimes I perpetrated against you all was senseless, extremely hurtful and inexcusable.

I humbly beg you your forgiveness, and pray you find the peace, healing, and closure, you all deserve. ... I'm not the person I was, I've been transformed. Some things can't be undone, I seek forgiveness."

10:52 p.m.: Execution begins

Williams continued speaking in tongues and moments later, a warden said they were ready to proceed with the execution, Associated Press reporter Kelly Kissel said.

The first of the lethal drugs, midazolam, was delivered.

Williams continued speaking in tongues until he switched to English. He was heard saying "these last words..." before he stopped talking.

10:55 p.m.: First drug takes effect

Witnesses could hear Williams' heavy breathing.

Williams body jerked about 15 times across 10 or 15 seconds, before moving five more times at a slower rate, Kissel said

Little Rock TV anchor Donna Terrell told CNN affiliate KARK-TV that Williams' chest started going up and down rapidly for several minutes.

"For about 10 seconds, his chest raised and lowered as though he was coughing but there was not coughing sound," reads a log of the execution. "His hands remained relaxed and he did not have a grimace or indication of distress on his face."

10:57 p.m.: Other drugs injected

After an attendant checked if Williams was conscious, two other drugs were administered.

He continued breathing heavily.

11:02 p.m.: Vital signs assessed

An attendant checked Williams' pulse and respiration. Then a warden summoned a coroner.

11:05 p.m.: Williams dies

A coroner pronounced Williams dead.

The curtains of the viewing room were closed and witnesses left.

Williams' body was taken from the chamber at 11:14 p.m.