The state of Arkansas on Thursday carried out its fourth execution in eight days, injecting 38-year-old Kenneth Williams with a three-drug cocktail that paralyzed him and stopped his heart. An Associated Press witness said Williams’s body jerked 15 times in quick succession as he was administered the drugs, before slowing for a final five movements. He was pronounced dead at 11:05 p.m. A spokesperson for Republican Governor Asa Hutchinson, who did not witness the execution, called Williams’s movements "an involuntary muscular reaction." An attorney for Williams called the claim a "whitewash" and called for an investigation. Arkansas rushed to carry out an unprecedented series of killings as its supply of the sedative midazolam was set to expire at the end of the month. Midazolam has repeatedly failed to make prisoners unconscious in other executions, leading to painful deaths. Arkansas carried out Kenneth Williams’s execution after the U.S. Supreme Court declined to intervene. Ahead of Thursday’s execution, the daughter of one of Williams’s victims, Kayla Greenwood, pleaded for the state to call off its plans, writing, "His execution will not bring my father back or return to us what has been taken, but it will cause additional suffering."