The Argus Leader, Elisha Page, File) NO SALES, Associated Press
FILE - This April 13, 2011 file photo shows Rodney Berget being escorted into Minnehaha County Court in Sioux Falls, S.D. Berget, convicted and sentenced to death for the April 2011 killing of Sioux Falls prison guard Ronald Johnson, in Sioux Falls, S.D., has been scheduled to be executed in May. Attorney General Marty Jackley says a judge issued a warrant of execution for Berget that calls for him to die by lethal injection sometime between Sunday, May 3, and Saturday, May 9.

SIOUX FALLS, S.D. — The second of two men who killed a South Dakota prison guard is scheduled to die by lethal injection in May, though it could be delayed with an appeal.

Rodney Berget, 52, is scheduled to be put to death sometime between May 3 and May 9, Attorney General Marty Jackley said Monday. The warden of the state penitentiary in Sioux Falls will choose the specific time and day and announce it within 48 hours prior to the execution.

Berget has twice delayed his execution through appeals. His defense attorney, Jeff Larson, said last month he would likely request a stay. Larson was out of the office Monday and unavailable for comment.

Berget was serving life sentences for attempted murder and kidnapping when he tried to escape in April 2011 with Eric Robert, who was serving 80 years in prison for a kidnapping conviction.

Penitentiary guard Ronald Johnson was alone in an area where inmates work on projects such as upholstery and signs when he was attacked with a pipe and killed. Robert then donned Johnson's uniform and tried to move a large box with Berget inside toward the prison gate, but they were caught before getting out.

Robert was executed in 2012. A third inmate, Michael Nordman, was sentenced to life in prison for providing plastic wrap and the pipe used in Johnson's slaying, which happened on his 63rd birthday.

Legal injections have come under scrutiny recently after the process took longer than expected in Ohio and Oklahoma. Sara Rabern, a spokeswoman for the attorney general's office, said those states are not using the single-drug pentobarbital protocol adopted by South Dakota.

Berget would be the 19th person to be executed in South Dakota. The other two men on the state's death row are Charles Russell Rhines and Briley Piper.