SAN PEDRO (CBS13) – Investigators used ground-penetrating radar to search the home of Ruben Flores, the father of Paul Flores, who is accused of Kristin Smart’s murder.

The technology used in Kristin’s investigation is the same that was used during the search for the body of Christie Wilson who vanished in Placer County in 2005.

So what is ground penetrating radar and how is it used? CBS13 is getting answers.

We turned to Placer County District Attorney Morgan Gire who says the technology isn’t new but is now being used more frequently forensically.

RELATED: Prosecutor: Kristin Smart Was Killed During 1996 Rape Attempt

The device uses radar pulses and can detect objects including underground irregularities. He says in the case of Christie, there was prior investigative information that helped detectives narrow down specific areas during their search.

“In Christie Wilson’s instance, we had a piece of property that was about 5 acres. So trying to figure out based on other avenues of investigation and intelligence where on that particular portion of that property would be ideal,” he said.

He says the radar also helps pinpoint underground spots that have been previously excavated or disturbed.

“And that may be a good area to prioritize in your investigation to try and see, potentially there might be that body that you are looking for there,” he added.

RELATED: A Timeline In The Disappearance Of Kristin Smart

Gire says the technology is an extra tool that can give families like Kristin’s hope.

“And for the investigators to know that there are other ideas, there are ways to think outside the box to try and never give up hope and never give up that we can find people,” Gire said.