A California man and his father pleaded not guilty Wednesday to the murder of Kristin Smart, a 19-year-old student who disappeared from her college campus 25 years ago.

Paul Flores, 44, and his 80-year-old father Ruben Flores entered the pleas during a pre-trial arraignment in San Luis Obispo Superior Court.

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Paul Flores pleaded not guilty to first-degree murder in connection with Smart’s suspected death in 1996 after an off-campus party at the California Polytechnic State University campus in San Luis Obispo. 

Ruben Flores pleaded not guilty to being an accessory to murder. Authorities allege the elder Flores helped dispose of Smart’s body, which has never been found.

Paul Flores, left, is charged with first-degree murder in connection to the suspected death of 19-year-old Kristin Smart. Ruben Flores, right, is charged with accessory after the fact. Prosecutors allege the elder Flores helped dispose of Smart's body, which has never been located. (Courtesy | San Luis Obispo County Jail.)

While Superior Court Judge Craig van Rooyen set a trial date for April 25, 2022, an attorney for Paul Flores said he plans to file a motion to dismiss the case, the San Luis Obispo Tribune reported. The motion is likely to be heard in January.

Paul and Ruben Flores were arrested in April in connection to Smart's disappearance. She was declared legally dead in 2002. Authorities said Paul Flores, who was a 19-year-old college freshman at the time, walked Smart home on May 25, 1996, and was the last person seen with her. 

Prosecutors said he killed Smart while trying to rape her in his dorm room.

Kristin Smart’s mother testified in a preliminary court hearing Monday.

This undated photo released by the FBI shows Kristin Smart, the California Polytechnic State University, San Luis Obispo, student who disappeared in 1996. Paul and Ruben Flores are both charged in connection with her purported death. (FBI via AP, File) (FBI via AP)

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During a preliminary hearing last month, prosecutors presented evidence that Smart's body was once buried under a deck shielded by lattice behind Ruben Flores's home. Prosecutors said the body had been moved from that location and it's never been located.

Traces of human blood were found under the deck along with stains in the soil and a disturbance in the earth the size of a human body, according to witnesses.

Van Rooyen said at the time that with the lack of DNA, "nothing links it definitively to Ms. Smart," but added that he had "a strong suspicion it was Ms. Smart’s remains."

Fox News’ Louis Casiano and The Associated Press contributed to this report.