Updated

A 15-year-old boy has pleaded guilty to killing a retired teacher at her East Tennessee home.

Media outlets report a Hawkins County judge sentenced Kyle Robert Wolfe to 25 years in prison without parole after he pleaded guilty Wednesday to second-degree murder in 79-year-old Margaret Sliger's May 2015 death. Wolfe was prosecuted as an adult.

Authorities say Wolfe was 14 when shot and stabbed Sliger. Her body was found in her yard.

The Kingsport Times News reports that Wolfe, who lived nearby, was suspected after investigators learned Sliger had confronted him for riding his four-wheeler in her pasture just before the slaying.

Sliger was a retired elementary school teacher and church organist. She raised chickens, cows and other animals on a family farm where she lived all her life.