The director of the Oklahoma Department of Corrections said Friday that he was resigning his office, the second prominent corrections official in the state to step down in recent months after multiple high-profile issues involving lethal injections in the state.

Oklahoma’s corrections department and the way it carries out executions has drawn national scrutiny since a botched, drawn-out lethal injection last year and two separate incidents this year when officials procured the wrong execution drug.

In the most high-profile incident, a convicted murderer, Clayton Lockett, grimaced and writhed during his lethal injection, and though authorities halted the execution, he died 43 minutes later. That drawn-out process prompted criticism from President Obama and the United Nations. Executions in the state were halted, and a state investigation later found problems with the training of the execution team.

Oklahoma’s lethal-injection process was also the focus of a case heard by the U.S. Supreme Court challenging the state’s use of midazolam, a sedative used in the drawn-out Oklahoma execution last year and two others that went awry. The justices ultimately upheld Oklahoma’s use of midazolam, and the state said it would resume executions.

However, a scheduled execution in September was halted at the last minute after it was determined that Oklahoma had obtained the wrong drug for that execution. The following week, state officials revealed that they had also gotten the wrong drug for an execution carried out in January, just days before the Supreme Court hearing on Oklahoma’s lethal injection protocol. Oklahoma announced not long after that it was delaying all executions scheduled for the rest of this year as a result.

Robert Patton, who was named the state’s director of corrections in January 2014, said he would officially resign at the end of next month because he had accepted a new job in Arizona.

“It has been an honor to serve this agency, the state of Oklahoma and to work with the talented people who make up the department,” Patton said in a statement.

Patton said he had accepted the new job to be closer to his family; a spokesman said he has five grandchildren in Arizona and wants to spend more time with them. According to the corrections department, he previously worked in corrections in Arizona, where he had been a correctional officer and eventually oversaw operations at numerous prisons.

Gov. Mary Fallin (R) praised his efforts to reform the department’s operations and focus on rehabilitation and treatment for non-violent offenders.

“I appreciate Robert Patton’s efforts to keep our state prisons safe for both correctional officers and inmates,” Fallin said in a statement. She added: “I regret his departure, but I understand the importance of family and the need to be close to loved ones. I wish him well in his future endeavors.”

Anita Trammell, the warden at the state penitentiary where the problematic executions occurred, said in October that she was retiring. A spokesman for the department said Trammell had been considering retirement in recent years, and said she was not asked by anyone else in the department to step down.