In Ohio, a teenage boy meticulously plotted for months to murder his neighbor, later boasting about the “disturbing” act online, according to officials.

Now 14, the teen confessed to charges of aggravated murder, aggravated burglary, and strangulation on Monday, accepting a plea agreement with prosecutors. Due to his age, his identity remains confidential, as reported by Cincinnati’s ABC affiliate WCPO.

The tragic incident unfolded in the early hours of February 2, when Sheila “Denise” Tenpenny was alone in her Fairfax home, located on Germania Street, a suburb of Cincinnati. As Tenpenny lay in bed, the teenager broke into her residence, delivering a brutal blow and subsequently strangling her to death.

Tenpenny, however, did not succumb without resistance. The Ohio Attorney General’s Office reported that the assailant was likely injured during the encounter, potentially bearing noticeable cuts or bruises on his face or hands. Investigators confirmed the suspect was male.

Upon arrival at the scene, law enforcement deemed the death of the 64-year-old woman “suspicious.” Tenpenny reportedly clutched strands of the boy’s hair, and his DNA was found under her fingernails. Additionally, she had scratched his face, leaving traces of his blood scattered throughout the home.

According to prosecutors, the boy left the woman’s home and returned to his social media network with a message: “This one was a fighter.”

It was not uncommon for the boy to be on the internet with killing on his mind, authorities said. He planned the murder for months, researching online and asking ChatGPT how to “choose the perfect victim,” how to strangle someone, and how to “defeat a police interrogation,” local NBC affiliate WLWT reported.

Ohio Bureau of Criminal Investigation Agent David Ward said that in his 20 years of working violent crimes, he’s never seen someone “of this age commit this type of crime.”

“And to add to that the premeditation of the offense is just chilling to me,” Ward said, per WCPO. “As the investigation went on and continued, his social media communications with individuals … there were several other communications that are very disturbing.”

“He made mistakes. He left his DNA; he tried to clean up the crime scene with items that wouldn’t have been successful,” the agent added. “It was good luck for us that he did make those mistakes, but in the future, is he going to learn from those mistakes? That’s what I’m concerned about.”

As part of the plea deal, the boy will reportedly be held at the Ohio Department of Youth Services until he turns 21, the oldest age that the agency can hold a juvenile convicted of a crime.

Tenpenny is remembered as having been “a beacon of light who touched the lives of many with her kind heart, unwavering resilience, and exceptional humor, leaving behind a legacy filled with valuable lessons and unforgettable memories that will continue to inspire those who were fortunate enough to know her.”