OKLAHOMA CITY — The Oklahoma Department of Corrections has increased security for its director following threatening phone calls and emails after a botched execution in April, according to records obtained by a newspaper.

The Tulsa World reported Sunday that records show the department bought a bullet-resistant sport utility vehicle with tinted windows for agency Director Robert Patton at a total cost of $40,587 and he is now accompanied by bodyguards.

Members of the Corrections Department’s Office of Inspector General serve as security and drive the vehicle when Patton travels

“After speaking directly with the Department of Corrections, there is a definite concern due to specific threats against the life of the Director of the Department of Corrections related to the recent execution case,” the office’s state fleet manager, Terry Zuniga, wrote in a May 22 email.

“I cannot in good conscience put him at risk,” Zuniga wrote. “As a result, Fleet will approve this request.”

The threats followed the April 29 execution of Clayton Lockett, who writhed on the gurney, moaned and clenched his teeth for several minutes after the lethal injection began.

He was subsequently pronounced dead of an apparent heart attack.