A Solano County Superior Court jury has convicted a man for the 1982 murder of a 14-year-old Vacaville high school student.

The jury on Thursday found 59-year-old Marvin Ray Markle guilty of murdering De Anna Lynn Johnson, a student at Will C. Wood High School whose body was found on railroad tracks not far from her home on Nov. 16, 1982. Prosecutors said Johnson was strangled and badly bludgeoned.

Markle was arrested in 2017 for the killing and was already serving an 80-year sentence in Kern Valley State Prison for another murder.

Markle, who was 17 years old at the time of the murder, was seen at a party Johnson attended the night before her body was found adjacent to Elmira Road near Royal Oaks Drive in Vacaville.

Markle was a suspect in the killing but the case went cold for three decades.

Vacaville police attended Markle’s trial in 2014 for the 2001 murder of 41-year-old Shirley Ann Pratt of Butte County, for which Markle was convicted and sentenced to the 80-year prison term.

After a three-week trial, the jury Thursday convicted Markle of first-degree murder with an enhancement for personal use of a deadly weapon.

Retired Vacaville police officers Joseph Munoz and Don Waller, who originally investigated Johnson’s murder more than 42 years ago, testified during the trial.

“I am so thankful for the dedication of the Vacaville Police Department and members of our office that no matter how much time went by they remained steadfast in their commitment to De Anna Lynn Johnson to solve her horrific case,” District Attorney Krishna Abrams said in a statement.