By CBSLA Staff

SAN PEDRO (CBSLA) — A San Pedro man pleaded not guilty Monday to murder charges in the case of Cal Poly San Luis Obispo student Kristin Smart, who was last seen walking back to the college dormitories from an off-campus party nearly 25 years ago.

An undated photo of 19-year-old Kristin Smart, who disappeared in May of 1996 while a student at California Polytechnic State University. (CBS News)

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Paul Ruben Flores, 44, — who had long been described as a “prime suspect” by authorities — and his 80-year-old father, Ruben Ricardo Flores, appeared via Zoom in front of San Luis Obispo Superior Court Judge Craig B. Van Rooyen Monday afternoon.

Flores is accused of killing Smart on May 25, 1996, during an attempted rape and his father is accused of helping him cover it up.

Prosecutors successfully argued Flores is a threat to public safety and a flight risk if released on bail. Rooyen ordered that Flores be held without bail, citing those concerns.

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44-year-old Paul Flores and his father 80-year-old Ruben Flores, following their arrests on April 13, 2021, in the 1996 disappearance of Kristin Smart in San Luis Obispo, Calif. (San Luis Obispo County Sheriff’s Office)

“I find that there is no less-restrictive means to protect public safety than to detain Paul Flores before trial,” Rooyen said. “This charge is obviously one of the most serious charges that can be alleged against someone and it carries a potential life sentence.”

He continued, “Mr. Flores has not remained crime-free since the alleged offense date.”

A bail review hearing was set for Wednesday for Flores’ father who pleaded not guilty to a felony charge of being an accessory to the fact.

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(© Copyright 2020 CBS Broadcasting Inc. All Rights Reserved. City News Service contributed to this report.)