A man was sentenced to 20 years in prison in connection to the 1998 murder of a woman found on Navajo tribal grounds, the Denver District Attorney’s Office announced Friday.

On June 30, 1998, 47-year-old Bonny Baker was reported missing. Her boyfriend, Crespin Nene-Perez, killed her and left her body in a shallow grave on Navajo tribal grounds within a day of her disappearance, according to the district attorney’s office.

In July 1999, two boys riding horses in a remote area of the tribal land discovered Baker’s remains. The New Mexico Office of the Medical Investigator took custody of her remains.

In Oct. 2012, the Denver Police Department’s Cold Case Unit reopened the case after it had gone cold. Officers worked with Navajo tribal officials in New Mexico, the FBI and the Denver Police Department Crime Laboratory to confirm the remains were Baker’s.

In 2013, a cold case detective completed witness interviews, along with forensic testing. The detective determined there was sufficient evidence to arrest Nene-Perez for Baker’s murder, the district attorney’s office said. Nene-Perez was living in Mexico when the case was filed. An arrest warrant was issued, and he was extradited in 2020 to face charges.

On March 25, 2022, Nene-Perez pleaded guilty to one count of murder in the second degree, according to the district attorney’s office. On Friday, Denver District Court Judge Eric Johnson sentenced Nene-Perez, now 58, to 20 years in prison.

“Violent crime cold cases are among the most challenging of all cases we handle, said Denver District Attorney Beth McCann. “However, thanks to the painstaking work of our Cold Case Unit lead by Chief Deputy DA Dawn Weber, justice may be delayed, but it is rarely denied. I am thankful for their work as well as that of the Denver Police Department’s Cold Case Unit and Crime Laboratory, the FBI, and many other agencies and individuals for solving this case and bringing Mr. Nene-Perez to justice.”