An Arizona man convicted of killing a college student in 1978 was put to death Wednesday after a nearly eight-year hiatus in the state’s use of the death penalty brought on by an execution that critics say was botched — and the difficulty state officials faced in finding lethal injection drugs.

Clarence Dixon, 66, died by lethal injection at the state prison in Florence for his murder conviction in the killing of 21-year-old Arizona State University student Deana Bowdoin, making him the sixth person to be executed in the U.S. in 2022. Dixon’s death was announced late Wednesday morning by Frank Strada, a deputy director with Arizona Department of Corrections, Rehabilitation and Reentry.

Dixon’s death appeared to go smoothly, said Troy Hayden, an anchor for the Fox10 TV news program who witnessed the execution.

The last time the U.S. state of Arizona executed a prisoner was in July 2014, when Joseph Wood was given 15 doses of a two-drug combination over two hours in an execution that his lawyers said was botched. Wood snorted repeatedly and gasped more than 600 times before he died.