WAGONER COUNTY, Oklahoma - An Oklahoma City teen entered a guilty plea Monday in a Wagoner County murder-for-hire scheme. Michael Richardson was sentenced to 28 years in prison on a charge of second degree murder in the death of his girlfriend's father, Arthur Burney.

Burney, 53, was shot in the head on February 18, 2011. His body was found in his barn near Coweta.

According to court records, Michael Richardson said his girlfriend Michelle and her mother Patricia paid him $6,000 to kill Burney. The victim's wife, Patricia Burney, was sentenced to life in prison in April for hiring Richardson to kill her husband.

Family members told News On 6 Patricia Burney wanted the life insurance money, and that Michelle Burney had been arguing with her father.

According to court records, the mother and daughter picked Richardson up in Oklahoma City and drove him to Coweta where he hid in the barn with a rifle. After Richardson shot Burney, the trio went to a Tulsa shopping mall, the affidavit states.

Patricia Burney is appealing her sentence. Michelle Burney pleaded guilty in juvenile court and testified in her mother's trial.