OKLAHOMA CITY - A shake-up in the Annie Hill murder case had the attorney for one defendant speaking out.

Prosecutors changed their mind about who they believe killed Hill, a 16-year-old Casady student who went missing in April 2014.

It was 17-year-old Chloe Thomas who first went to police last year, implicating herself and co-defendant Chadd Raymond in Hill's disappearance. Thomas's defense attorney, Michael Trevino, told News 9 they were under the impression that Thomas would get some sort of deal in exchange for her confession.

That was before last Friday. 

"We didn't see it coming," said Trevino.

Trevino said, by cooperating with the investigation, his client was trying to make things right.

"She told them what happened, she told them how she got to that situation," explained Trevino, "and she told them who killed Annie."

Now, Trevino said, he and Thomas feel that she's been wronged.

"The state would not have either one of these two, if my client hadn't come forward," said Trevino.

Thomas and Raymond were arrested last October in connection with Hill's presumed murder. The young woman's body has never been found.

Raymond was first looked at as the killer, but prosecutors said they are now convinced Thomas also had a hand in the murder, a contradiction to her confession.

"Obviously, they no longer believe my client and, thankfully, it will be a jury of 12 Oklahomans that will decide whether she is lying or not," said Trevino. "And we just look forward to a speedy day in court."

Prosecutors charged Thomas with first degree murder Friday and, in turn, made a deal with Raymond. He pleaded guilty to murder and will serve 35 years of a life sentence in exchange for his testimony. 

Raymond allegedly told investigators that it was Thomas who masterminded what started as a plot to rob Annie Hill and take her car. In April, the two allegedly lured Hill to Raymond's brother's apartment in Edmond, but, when everything did not go as planned, Raymond panicked and decided he had to kill Hill.

Raymond will reportedly testify that he began choking Hill but became too tired, so Thomas took over and finished the job.

"They believe he has given a truthful version of what goes on," Trevino said. "But as this case develops and unfolds, I think we will all see that his involvement in it is a little more than what he has said so far." 

Thomas's attorney said the only good he sees coming out of the state making a deal with Raymond is if he can lead investigators to where the two dumped her body. As part of the plea agreement, Raymond must reportedly accompany law enforcement in a search for Hill's remains.

Prosecutors declined to comment on an open case.