Harn told The Associated Press Monday that he excavated three sites Saturday identified by cadaver-sniffing dogs.
Drew Peterson is a suspect in Stacy Peterson's disappearance. He's in custody at the Will County Jail while awaiting trial for the murder of a previous wife. The 56-year-old former police officer is a suspect in the disappearance of Stacy Peterson. He's denied wrongdoing.
Harn says the tip about the site came from "a representative" of someone in jail. He declined to say more.
The search in a remote, muddy area near Peoria is based on what state police also called a "credible lead" in the case.
The attorney for Stacy's husband borrowed from Shakespeare Saturday, saying it was much ado about nothing.
Yet, there was enough in a tip of unknown origin to send an entire investigative team and all their gear 140 miles away to dig in the woods -- for something.
Investigators set up a canopy to provide cover in a small area where they were digging. The site was located approximately one mile off the road on a heavily wooded farm outside of Peoria, Ill. The Kickapoo Creek flows nearby.
Authorities were calling it a possible crime scene, but they wouldn't say specifically what they were looking for or what brought them to the site.Investigators wouldn't say if they found anything of interest Saturday but that they intend to return to the site.
"I don't want to allude to looking for a body. We're looking for evidence of a crime based on this lead that we have," Burek said.
Peoria County Coroner Johnna Ingersoll confirmed forensics teams were summoned to the scene and that excavation work was under way to search for human remains. The coroner also said no human remains had been found as of Saturday.
The team on-site consisted of detectives working the disappearance, joined by a forensic anthropologist.
There were early reports that the search might have been the result of a tip from an inmate in the Will County Jail. But Drew Peterson is in isolation, and his attorneys say he has no contact with any other inmates.
"I'm not saying a person gave us the tip. It's a lead the investigation team has. Where they got the lead, I'm not in a position that I want to comment on that at this stage," said Burek.
Rains reduced the land at the search site to a "muddy mess," meaning that parts are inaccessible by vehicle and investigators have had to comb the area on foot, Burek said early Saturday.
"The only thing that connects to all these leads, all these rumors, is each and every one of them has turned out to be false. Each and every one of them has turned out to be without basis, and each and every one of them turned out to be nothing but gossip," said Joel Brodsky, Drew Peterson's attorney.
On Saturday, Brodsky released a statement that read in part, "There has never been one, single factual piece of evidence regarding either Stacy's disappearance, or in the death of Kathy Savio, that shows that Drew is guilty of any wrongdoing whatsoever."
He also called the most recent search "patently ridiculous."
"Drew's position from day one has always been that she ran off with another man because that's what she told him," Brodsky said.
Countless searches have taken place since Stacy Peterson vanished in October 2007. She was 23 years old at the time.
Drew Peterson's third wife, Kathleen Savio, was found dead in an empty bathtub in 2004. Her death was initially ruled accidential but then changed to a homicide after prosecutors reopened the case following Stacy Peterson's disappearance.
On Saturday, those who knew Stacy Peterson just wanted and hoped for closure.
" It was incredibly emotional. It'll bring a lot of closure. Her family and friends really need that," said family friend Jamie Holt.
Her family, including her aunt, said they were unsure what to make of Saturday's search.
"We just want to know where she's at. That's what we want to know. It would mean everything to us. We want to find her and bring her home," aunt Candace Aikin said.
The owner of the property where the search was conducted says police told him they had solid leads and specific coordinates for their search.
(The Associated Press contributed to this report.)