Investigators worked behind yellow crime scene tape and utilized ground-penetrating radar Monday after a search warrant was served at the Arroyo Grande home of Ruben Flores, the father of the prime suspect in the disappearance of Cal Poly student Kristin Smart.

San Luis Obispo County sheriff's officials also received authorization to utilize cadaver dogs at the home in the 700 block of White Court, according to Tony Cipolla, who said the search could last into Tuesday. 

Crime scene tape sealed off access to the house, which had several "no trespassing" signs posted on the split rail fence surrounding the property. A sheriff's RV and portable toilets were also on-site due to the anticipated length of the search, Cipolla said. 

Throughout the day, investigators were seen moving a ground-penetrating radar back and forth across sections of the backyard and a portion of ground underneath the porch. Rain in the early afternoon briefly halted operations, which quickly restarted.

Sheriff's officials could not provide further details about the day's developments because the search warrant has been sealed. 

Smart has been missing since May 25, 1996, after she walked away from an off-campus party and was never seen again. Her body has never been recovered, although she was declared legally dead in 2002. 

The Cal Poly freshman was last seen walking back to her dorm room with Paul Flores, a 1995 Arroyo Grande High School graduate, who was also attending classes at the university at the time of Smart's disappearance. 

Although no charges have ever been filed in the ongoing and active investigation, the San Luis Obispo County Sheriff's Department has considered Paul Flores a person of interest from the beginning. 

Cammie Karamanalis, 28, carried her toddler daughter with her as she walked toward the Flores house on Monday, snapping pictures with her iPhone along the way. She lives within sight of Ruben Flores' house, and she said the Smart case has haunted her since she was a student at Cal Poly. 

"I can see the house directly from my daughter's bedroom window," Karamanalis said. "It makes me so uneasy." 

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Access to the road leading up to the cul-de-sac of the Flores' home was restricted on Monday, although media and residents nearby were given access. 

Orcutt native Chris Lambert, the publisher of the wildly popular "Your Own Backyard" podcast that featured episodes on the Smart case, was on scene Monday to document the day's events. 

Sandy Danger, a radio DJ for 95.7 FM in Santa Maria, has closely followed the case and immediately drove to the scene of the search to witness events for herself. After years with no arrests and no results from earlier warrants, Danger is hoping this time will be different. 

"We all want closure for the family," Danger said. "It's so disappointing when nothing comes out." 

The search comes a month after Paul Flores' arrest on Feb. 11 on suspicion of possessing a firearm as a convicted felon in Los Angeles County. In April 2020, sheriff's officials served a search warrant at his Los Angeles residence as they sought to retrieve specific items of evidence. The nature of those items has not been disclosed. 

Four warrants also were served in California and Washington state in February 2020. All five of those warrants remain sealed.