By Steve Gorman

(Reuters) -A former classmate of Kristin Smart, the California college freshman whose 1996 disappearance had long been one of the state's most sensational unsolved crimes, was found guilty on Tuesday of first-degree murder for her death.

The guilty verdict against Paul Flores, 45, was returned by a 12-member jury in Monterey County Superior Court at the end of a three-month trial. He was arrested and charged with Smart's death in April last year.

Flores faces a maximum penalty of 25 years to life in prison when sentenced on Dec. 9.

"Today, justice delayed is not justice denied," San Luis Obispo County District Attorney Dan Dow told a news conference.

A separate jury acquitted the defendant's father, Ruben Flores, 81, accused of helping to hide Smart's body, of being an accessory to murder after the fact.

Smart, who was 19 when she went missing, was last seen walking to her dormitory on the campus of California Polytechnic State University in San Luis Obispo, about 150 miles (240 km) northwest of Los Angeles, at about 2 a.m. on May 25, 1996. She was returning from an off-campus party.

Prosecutors alleged Paul Flores killed her during a rape or attempted rape. Her remains have never been recovered although investigators have said they searched 18 locations for her body.

Flores, long the main suspect in her disappearance, had told investigators he had left the same gathering with Smart but parted company from her about a block from her dorm.

Prosecutors and Sheriff Ian Parkinson both credited a 10-part documentary podcast, "Your Own Backyard," launched by freelance journalist Chris Lambert in 2019 with unearthing new evidence and witnesses that helped investigators crack the case.

Delays in the investigation of the case prompted state lawmakers to pass legislation requiring colleges and universities to share information more quickly about missing students with off-campus police.

According to a courtroom account published by the San Luis Obispo Tribune newspaper, Paul Flores flinched as the guilty verdict was read. The victim's father, Stan Smart, reacted with a smile and put his around her mother, Denise Smart, who was in tears.

Defense lawyer Robert Sanger told The Tribune afterward that "the case is still pending," but declined further comment. During his summation to jurors, Sanger asserted there was "no evidence of a murder."

The trial was moved from San Luis Obispo County in a change of venue requested by defense lawyers because of intense pretrial publicity surrounding the investigation.

Sheriff Parkinson vowed that the case would remain open until the victim's remains are found and returned to her family.

Stan Smart, speaking to reporters following the trial, expressed his appreciation of the outcome but added, "Without Kristin, there is no joy or happiness in this verdict."