A 21-year-old Washington State man pleaded guilty Friday to the rape and murder of a 6-year-old girl whose body was found in a muddy bog several years ago, the Kitsap Sun reports.

Gabriel Gaeta, who was 17 at the time of the crime, faces 40 years to life behind bars.

Authorities say Gaeta sexually assaulted the girl, Jenise Wright, who was a neighbor and the sister of one of his high school friends. Gaeta then strangled her to death.

She was reported missing on Aug. 3, 2014, and her disappearance triggered a massive search effort.

In the course of that search, police reportedly obtained DNA samples from neighbors and matched Gaeta’s DNA with material from Jenise’s underwear, court records state.

Wright would have been 11 years old this year.

The case took three and a half years to resolve because issues with Gaeta’s mental health and changing standards for how the law treats juveniles in the criminal justice system, the newspaper reports.

Attorneys for both the prosecution and defense have agreed to recommend the minimum 40-year sentence against Gaeta, who was charged with aggravated first-degree murder and first-degree rape of a child.

Denise Wright, the mother of Jenise, told the newspaper she’s glad the case is nearing an end.

“I’m just glad he pled guilty,” she said.

Chief Deputy Prosecutor Chad Enright told reporters that Gaeta’s guilt was “painfully obvious.”

“The evidence in this case was incredibly strong,” Enright said. “The investigation was thorough, there was no doubt he was going to be convicted and so having him finally acknowledge that I think is important to the community and important to Jenise’s family.”

Gaeta, then a senior in high school, was charged as an adult. The case stalled because of multiple problems that arose with his mental health. At one point he was found incompetent to stand trial after he cut off communications with his lawyers.

His mother told authorities that she had concerns about his mental health even before the killing.

“This never would have happened if (Gaeta) had gotten the help he needed,” said Tina Wright, Gaeta’s mother.

Tina Wright is not related to Denise Wright, the victim’s mother.

[Feature image: Jenise Wright/Facebook]