Man Tries to 'Stage' Girlfriend's Death with 'Post-It' Suicide Note, Confesses Truth in Jail: Prosecutors

She was suffering from a single gunshot wound to the neck and had a gun in her hand. The victim was pronounced dead on the scene.

As they began to investigate the scene, officers discovered a "Post-It Note" in a downstairs bedroom, according to a press release from the Peoria County State Attorney's Office, that appeared to paint a picture of what might have happened.

The note purportedly read, "I, Mary Elyce Halcomb, promise to never break Nathanial Archuleta's heart, and if I do, Nathaniel Archuleta has every right to euthanize me, vice versa, I love you."

Nathan Archuleta, 19, reportedly gave police "conflicting accounts" of what happened that night as investigators started to rule out suicide as the possible cause of Halcomb's death. A large factor in this was a blood trail from the bedroom to her final resting place in the landing area, suggesting her body had been moved after she was shot.

An autopsy of Halcomb's body also revealed that the gun that had shot her in the neck was fired from two to three feet away, per the Peoria JournalStar at the time.

While speaking with detectives, Archuleta first told them that his girlfriend had committed suicide. Then, his story shifted to an admission that he'd been cleaning his gun and it accidentally went off, though police could not find anything that could be used to clean a firearm in the home.

That explanation also does not explain why her hand was wrapped around the gun on the landing, with prosecutors arguing in court Monday that Archuleta "staged her death to appear as a suicide."

According to the State Attorney's press release, though, Archuleta allegedly made a jailhouse confession, telling a fellow inmate that he had shot Halcomb because he "caught her texting another man."

In a report at the time of his arrest by local radio station WMBD, Archuleta also allegedly "admitted to signing the sticky notes."

In court on Monday, prosecutors talked about how her loss has impacted her family. "They spoke of sleepless nights, nightmares, and persistent heartbreak. They described their overwhelming sense of loss, loss of sisterly moments, shared dreams, and life milestones that will never come," they said, per the release.

"Mary's loved ones described struggling with trust, fear, depression, and anxiety," prosecutors continued. "They called Archuleta's actions selfish and unforgivable, stating that blood will forever be on his hands and that justice must now be served."

During the hearing, Nathaniel Archuleta pleaded guilty to the first-degree murder of Mary Halcomb. His trial had been set to begin July 28, per the Peoria JournalStar.

As part of his plea agreement -- which is supported by Halcomb's family, according to the State Attorney's Office -- he was sentenced to 45 years without the possibility of parole.

In her obituary, it was revealed that Halcomb was working as a CNA while attending classes toward becoming a nurse, "a goal driven by her deep compassion and desire to help others."