SPRINGFIELD, Ill. — Fifteen months after Sonya Massey, a Black woman who had called 911 for help, was killed in her home, the former police officer who fired the fatal shot is set to go on trial.

Sean Grayson, 31, a former deputy for the Sangamon County Sheriff’s Department in central Illinois, has pleaded not guilty to three counts of first-degree murder.

The trial was scheduled to begin Wednesday with opening statements. If convicted of murder, Grayson faces a sentence of 45 years to life in prison. Prosecutors dismissed single counts of aggravated battery with a firearm and official misconduct.

On July 6, 2024, Massey, a 36-year-old single mother of two teenagers who struggled with mental health issues, called emergency responders over a suspected prowler. When Grayson, who is white, and another deputy entered her Springfield home to report finding no one, Grayson noticed a pan of hot water on the stove and ordered it removed.

According to body-camera video that is certain to play a key role in the trial, Grayson and Massey joked about how the deputy backed away as she moved the pan before Massey said, “I rebuke you in the name of Jesus.” Grayson later told sheriff’s investigators he thought Massey’s statement meant she intended to kill him, yelled at her to drop the pot and in the subsequent commotion, fired three shots, striking her just below the eye.

The incident has prompted continued questions about U.S. law enforcement shootings of Black people in their homes and generated a change in Illinois law requiring fuller transparency on the background of candidates for law enforcement jobs.

A jury of 10 women and five men, including three alternates, will hear testimony that’s predicted to end next week. The questioning of prospective jurors on Monday by Sangamon County State’s Attorney John Milhiser and defense attorney Daniel Fultz focused on attitudes toward law enforcement during a volatile time in America.

Witnesses scheduled to testify for both the state and defense are reported to be experts in police training, generally accepted police practices, use of force, body camera video, use of video in investigations and the review of incidents involving the use of force.

The national attention the case has garnered prompted Sangamon County Circuit Judge Ryan Cadagin to move the trial from Springfield to Peoria, 167 miles (269 kilometers) southwest of Chicago.