(Editor’s note: an earlier version of this story indicated that Trevor Mercier could face the death penalty at his sentencing. While the death penalty is a potential outcome of a deliberate homicide conviction, prosecutors say the criteria in this case did not warrant it. The story has been updated to reflect the correct potential sentences he may face.)

Trevor Mercier, the Libby man charged October 2016 in the death of Sheena Devine, was convicted Thursday, Aug. 10 of deliberate homicide and tampering with evidence. The jury took little over an hour to return the verdict.

Prosecutors say Mercier could face life in prison without parole or not less than 10 years or more than 100 years at his sentencing, scheduled for 10:30 a.m. Oct. 10, 2017.

Devine’s body was found in her home by her two young daughters on Oct. 6, 2016. Investigators arrested Mercier in his home the following day after identifying him as a prime suspect in her death, which they determined had occurred Oct. 5. Mercier and Devine had been in a relationship that had ended before the incident.

The conviction followed seven days of testimony that Alicia Backus, an attorney for the defense, in her closing remarks acknowledged had been “an emotional roller coaster.”

Mercier’s defense acknowledged at trial that he had caused Devine’s death but that it was a case of negligent, not deliberate, homicide, because he did not intend to kill her. In her closing statements Backus told the jury that the prosecution had failed to prove beyond a reasonable doubt that Mercier was guilty of deliberate homicide.

The night of Devine’s death, she and Mercier had fought after Mercier threw a rock at her car, smashing its windshield. The defense said while fighting Mercier put Devine into a “sleeper hold,” rendering her unconscious. Afterward, the defense said, Mercier took her inside her house, placed her on the floor, checked to make sure she was still breathing and then left the house.

In her closing statements Backus said Mercier’s actions that night “created the perfect storm” but were not deliberate.

The prosecution on Friday, Aug. 11 called an expert witness — Dr. Jaime Oeberst — to the stand to support its assertion that Mercier did in fact deliberately cause Devine’s death. Now a deputy coroner in Kansas, Oeberst performed the autopsy on Devine on Oct. 8, 2016. Referring to autopsy photos projected onto a screen, Oeberst testified to the nature of Devine’s injuries and also to how strangulation occurs.

To underscore the difference between the 10 to 15 seconds a “sleeper hold” takes to render someone unconscious and the three to five minutes that can cause death, Deputy County Attorney Marcia Boris instructed Oeberst to use her watch to time the passage of five minutes — during which the court was silent but for the occasional paper shuffling or person fidgeting.

Deputy County Attorney Jeff Zwang referred to that dramatic demonstration in his closing remarks, stating that Mercier had “strangled (Devine) long after she was unconscious” and that he had beaten her so badly that she had hemorrhages all around her head and sternum.

In wrapping up the prosecution’s closing statement, Boris reminded the jury to consider Mercier’s previous conviction for a February 2016 domestic assault against Devine — an assault that moments before Backus had minimized in her closing statement because a counselor had said post-conviction that a no-contact order put in place should be lifted.

In addition, Mercier’s attorneys were critical of aspects of the investigation, including law enforcement’s handling of the crime scene.

Lincoln County District Court Judge Matt Cuffe scheduled Mercier’s sentencing for 10:30 a.m. Oct. 10, 2017, after a pre-sentence investigation has been completed.