IDAHO FALLS — A man who reportedly killed his stepfather in September pleaded guilty Tuesday.

Westley Hightower agreed to plead guilty to first-degree murder. The plea agreement was reached earlier that day, with both the defense and the prosecution agreeing to a last-minute change.

Defense Attorney Rocky Wixom agreed that he would recommend no less than a 20-year fixed term, while Chief Deputy Prosecutor Alayne Bean said she would recommend no more than a 27 year fixed sentence. Both sides agreed to an indeterminate life sentence.

“On the day of Sept. 28 of last year, I took the life of Larry Powell,” Hightower said to District Judge Dane Watkins Jr.

The original plea agreement would have allowed Wixom to recommend no less than 15 years while Bean would have been limited to a maximum of 30 years fixed. The agreement was changed during the hearing after Wixom and Bean discussed the case privately.

The plea agreement is non-binding, meaning Watkins can sentence Hightower to more or less time than recommended by the parties without it being grounds for Hightower to withdraw from the agreement.

Hightower and his co-defendant, 18-year-old Daniel Wood, were arrested after they reportedly killed Powell. The shooting happened one day before Hightower’s 18th birthday.

Court records state Wood distracted Powell, 68, while Hightower shot him in the head. The pair had also reportedly conspired to kill Hightower’s adoptive mother by sabotaging her car.

Wood told police Hightower hated Powell. He said Hightower offered him money to help with the killing and that Hightower told him he could live in Powell’s house after they killed him. Wood was homeless at the time.

Hightower admitted to shooting Powell after his arrest, saying he had wanted Wood to do it.

Wixom said Hightower had struggled to understand the weight of what was happening in the case, but added that he believed Hightower was competent to reach a decision “intelligently.”

Wixom also said he would have experts evaluate Hightower in the months before sentencing, though he did not specify what condition he thought Hightower may have.

Hightower is scheduled to be sentenced Nov. 8. Wood has pleaded not guilty to first-degree murder. A pretrial conference is scheduled for Aug. 2.