Kristin Smart case: father and son arrested 1:46
(CNN) -
The man accused of killing 19-year-old college student Kristin Smart in 1996 has pleaded not guilty at his appearance Wednesday.
Paul Flores, 44, faces a first-degree murder charge for allegedly killing Smart in his bedroom in California.
Prosecutors say Flores raped or attempted to rape Smart, who was then a freshman at California State Polytechnic University in San Luis Obispo.
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Flores and her father were arrested in April after a 25-year search to find Smart, who was last seen near her Cal Poly bedroom on May 25, 1996. She was never found and was pronounced dead in 2002.
Rubén Flores, 80, who faces an accessory charge, also pleaded not guilty.
Prosecutors have said it helped hide Smart's body.
His next court date is at a pretrial hearing on Dec. 6.
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Paul Flores has been the prime suspect in the case for decades.
Authorities have said Flores, who was a 19-year-old freshman at the time, accompanied Smart home and was the last person to see her that day.
In documents filed in the case, a sheriff's office detective stated that investigators are "in possession of biological evidence that leads them to believe that the victim was buried under (Rubén Flores') deck at one point."
CNN's Steve Almasy and Eric Levenson contributed to this report.