Oklahoma man set to be executed for killing his ex-girlfriend and her 7-month-old daughter

This image provided by the Oklahoma Department of Corrections shows Raymond Johnson. (Oklahoma Department of Corrections via AP)

McALESTER, Okla. (AP) — An Oklahoma man convicted of killing his ex-girlfriend and her 7-month-old daughter after setting their home on fire nearly 20 years ago was set to be executed on Thursday.

Raymond Johnson, 52, was scheduled to receive a lethal injection at the Oklahoma State Penitentiary.

He was condemned for the June 2007 death of 24-year-old Brooke Whitaker and her 7-month-old daughter, Kya.

Prosecutors said that after Johnson and Whitaker got into an early morning argument at her home in Tulsa, he repeatedly hit her over the head with a metal claw hammer.