The FBI combed the brown hillside below Cal Poly's dorms and painted "P" on Wednesday as members of the evidence response team searched for anything that would lead them to Kristin Smart, who vanished 20 years ago.

Smart was last seen alive on May 25, 1996, when she was standing just steps from her dorm at Muir Hall, which sits below the hillside that the FBI is excavating for human remains. 

"The FBI started digging in full force this morning," Sheriff's Department spokesman Tony Cipolla said Wednesday morning. "There are three areas of interest, and they are at the first location."

Cipolla said the FBI has backhoes, end loaders and teams of individuals hand-sifting the dirt in an effort to find any evidence related to Smart or her disappearance.

On Tuesday, San Luis Obispo County Sheriff Ian Parkinson said a lead was developed over the last two years strongly suggesting Smart may be buried on the hillside near the "P," painted stones shaped into the letter. 

The Sheriff's Department brought in specially trained cadaver dogs earlier this year as it worked the lead. Those dogs, which are trained to detect aged human decomposition, keyed in on several locations in the county, including the hillside at Cal Poly. Parkinson declined to disclose the other locations Tuesday.

The Smart family declined to speak directly to the media but released a statement Wednesday that, in part, said they are encouraged and hopeful by the new developments in the case.

"We have been hoping, praying and waiting for the last 20 years for the return of our daughter," said Denise Smart, Kristin's mother. "And while the road has been difficult beyond words, our hopes were rekindled when Sheriff Parkinson took office."

She added, "We are mindful that with or without the hoped-for results from this week's efforts, we are now on a path that will bring our family peace and comfort."

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Cipolla said Wednesday no other locations currently are being excavated, as law enforcement is focusing all of its efforts on the Cal Poly sites. However, if nothing is discovered at the campus, those other sites likely will be investigated in the future.

"This was a massive undertaking," he said, adding the FBI expects to be finished with the dig Friday, which he called a "buffer day." 

If the dig shuts down as planned Friday depends on whether any evidence is recovered during the search, Cipolla said.

Dennis Mahon, a close family friend who has been involved in helping search for Smart since the beginning, said if the FBI's dig yields no evidence, he and others plan to aggressively push law enforcement to dig up the entire backyard of a home Paul Flores' mother, Susan Flores, owns in the Village of Arroyo Grande. 

No charges ever have been filed in the case; however, the Sheriff's Department has considered Flores, a 1995 Arroyo Grande High School graduate, a person of interest from the beginning. He was the last person seen with Smart. 

"Kristin has long deserved the attention, effort and respect that Sheriff Parkinson, his department, the FBI, the district attorney and Cal Poly are giving to her recovery and our quest for justice," Denise Smart said. "We are confident that the ‘person of interest’ will soon be held accountable for taking her life and harboring her remains for over 20 years."

Crews were expected to work the dig site until sundown and resume efforts at 7 a.m. Thursday.

The entire Cal Poly campus was searched after Smart went missing, but her body was never found. She was declared legally dead in 2002.

April Charlton writes for Lee Central Coast Newspapers. Follow her on Twitter@WordsDawn