In the spring of 1996, Kristin Smart, a 19-year-old college student, left an off-campus party in San Luis Obispo, Calif., and walked home to her dormitory.
She was never seen again. No remains have been found.
But on April 13, 2021, after an investigation that spanned nearly a quarter of a century, the authorities announced that two California men — Paul Flores, 44, and his father, Ruben Flores, 80 — had been arrested in connection with her disappearance.
In a statement, the Smart family described a long wait for “this bittersweet day.”
“It is impossible to put into words what this day means for our family,” they said. “We pray it is the first step to bringing our daughter home.”
Here is a timeline of the Smart case.
May 25, 1996
Ms. Smart, who was from Stockton, Calif., was a freshman at California Polytechnic State University in San Luis Obispo. On May 25, 1996, friends dropped her off at an off-campus party. She left around 2 a.m., and was accompanied by Paul Flores, who was also a student at Cal Poly. He later told investigators that he walked her as far as his dorm, where they parted ways.
A missing-person report was filed with the campus police on May 28.
The next month, the San Luis Obispo County Sheriff’s Office took over from the Cal Poly police as the lead investigators.
The search for Ms. Smart, who was nicknamed “Roxy,” took many forms. Soon after her disappearance, a sheriff’s search party combed remote parts of the Cal Poly campus on horseback, archival video from KCRA-TV shows. Helicopters were used to canvas the area. The police searched her dorm room in Muir Hall, finding her wallet and reminders to turn in assignments. Cadaver dogs were sent into Paul Flores’s dorm room.
Paul Flores was identified as a “person of interest” early in the case. He has denied any involvement.
Missing-person posters and billboards offering rewards appeared along roads and in other public places. Ms. Smart’s acquaintances were interviewed. They described dropping her off at the party at an unofficial fraternity house, and said that when it was over, she needed support to walk as she was being accompanied home by Paul Flores.
The Smart family filed a $40 million wrongful death lawsuit against Paul Flores in 1997, but he was not immediately charged criminally in the case. He refused to answer questions during a deposition in November 1997, citing the Fifth Amendment.
Ms. Smart’s family declared her legally dead in 2002, but the search, and the investigation, continued. In 2004, the family sought donations to keep billboards up along Highway 101 to maintain awareness of the case, The Los Angeles Times reported.
Cadaver dogs trained to detect human decomposition were deployed by the F.B.I. to search on and near the Cal Poly campus. One of those areas was a hillside above the campus. In 2016, earthmovers carved into the soil there but did not turn up remains.
The Sheriff’s Office investigators and forensic specialists assigned to Ms. Smart’s case executed 18 search warrants, submitted 37 items that were collected in the early days of the case for DNA testing, recovered 140 new items of evidence and conducted 91 interviews from 2011 to 2020, the office said.
The authorities began to describe Paul Flores as a “prime suspect” in the case. Two trucks that belonged to members of the Flores family in 1996 were taken as evidence. In February 2020, the authorities executed search warrants at four locations in California and Washington State and recovered what the San Luis Obispo County Sheriff’s Office described as “items of interest.” One location was the Los Angeles home of Paul Flores, KCAL-TV reported.
In March 2021, investigators used cadaver dogs and ground-penetrating radar to search Ruben Flores’s property in Arroyo Grande, Calif.
Paul Flores was taken into custody at his home in the San Pedro section of Los Angeles on April 13, 2021, and was charged with murder. Ruben Flores, 80, was arrested at his home on the same day and was charged with being an accessory after the fact.
The next day, Dan Dow, the San Luis Obispo County district attorney, said that Paul Flores “caused the death” of Ms. Smart “while in the commission of, or attempted, rape.” Ruben Flores helped to hide her remains, he said.
Ms. Smart’s family released a statement after the arrests were announced.
“We now put our faith in the justice system and move forward,” they said, “comforted in the knowledge that Kristin has been held in the hearts of so many and that she has not been forgotten.”