During a press conference on Wednesday, San Luis Obispo County District Attorney Dan Dow said Kristin Smart was killed during an attempted rape and Paul Flores' father helped hide her body.
Dow added that they "do have evidence in this case that leads us to conclude that there very well may be additional victims in the southern California area."
Dow charged Paul Flores with first-degree murder during the commission of attempted rape. Dow added that the statute of limitation for rape has expired, but the allegations that rape was committed or the attempt of rape is the basis for filing a felony murder charge.
"These charges mark a milestone. For more than two decades law enforcement agencies have worked to bring justice for Kristin Smart," Dow said.
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Ruben Flores is charged with accessory after the fact since he helped conceal the body of Smart after the murder, Dow said.
They are both will be arraigned Thursday morning.
The two were arrested Tuesday at their separate homes connected with the disappearance of 19-year-old Cal Poly freshman Kristin Smart, who was last seen on campus on May 25, 1996.
According to a witness, Smart was last seen with Paul Flores leaving an off-campus fraternity party in San Luis Obispo and walking back to her dorm.
Paul, 44, is being held without bail on suspicion of murder.
Ruben, 88, is being held on accessory to murder after the fact. His bail is set at $250,000.
Following their arrests, San Luis Obispo County Sheriff Ian Parkinson said the case had been forwarded to the district attorney’s office for review.
The San Luis Obispo County Sheriff’s Office was back at Ruben’s home on White Court in Arroyo Grande Wednesday morning, where crews the day prior appeared to be digging and dismantling the back deck area as part of a search warrant.
During a press conference on Tuesday, Parkinson said that while Kristin’s remains have not been found, he believes they are closer than ever finding her.
Parkinson added that law enforcement found physical evidence at two homes. He would not disclose what evidence was found nor which two homes the evidence was found at.
She would have been 44-years-old this past February.
KSBY first reported this story.