Police said Friday they had called off the search for Jennifer Wilbanks (search) and also asked her fiancé to undergo an officially administered polygraph test.

"We've turned over every leaf in this city. I have suspended all future searches" until more evidence is found, Duluth Police Chief Randy Belcher told reporters.

Earlier Friday, Wilbanks' uncle offered a $100,000 reward for the capture of anyone connected to her disappearance. Mike Satterfield tearfully told reporters the family was praying for Wilbanks' safe return and pleaded the case not be turned into a circus.

"We love Jennifer very much. We would give our life and everything that we own to have her returned," Satterfield said.

Belcher said John Mason (search) passed a privately administered lie detector test but that authorities were asking him to take a polygraph given by either the FBI or the Georgia Bureau of Investigation (search).

Mason's attorney, Jim Watkins, has set forth conditions for an official polygraph, including that it be videotaped, which is not procedure for an official test.

Belcher said no law enforcement agency "that's worth anything" will agree to videotape a lie detector test.

Dr. Larry Kobilinsky, a professor of forensic science at the John Jay College of Criminal Justice, told FOX News that it makes sense Mason would want to take more than one test because they can produce false positives.

"This is a little suspicious but I am not surprised there are two tests," Kobilinsky said.

Belcher said the search for the missing bride-to-be had been called off because of a lack of evidence. Belcher did say a clump of hair found Thursday was being analyzed and that it was similar to Wilbanks' hair in type and color. Belcher said the hair was cut and not yanked from the scalp.

Clothing items that have been found, a gray sweatshirt and blue sweatpants, were also being analyzed by investigators.

In addition, police were inspecting two computers seized from the home Mason and Wilbanks shared to see if the bride-to-be had made contact with people on the Internet.

Mason was set to marry Wilbanks on Saturday, but he said she disappeared Tuesday during her nightly jog in their Atlanta suburb. Authorities are treating the case as a criminal investigation.

Her keys, cash, credit cards and identification were found in her home. Mason said she left with only her radio and the clothes she was wearing.

Mason, who had just returned from a run himself, said Wilbanks prefers to run by herself, but "she doesn't just go and run and hide."

Police gave mixed signals about whether they believe Wilbanks, a hospital nurse, may have gotten cold feet four days before her wedding.

Maj. Don Woodruff said authorities did not believe Wilbanks was a runaway bride. But under questioning from reporters, Belcher later said: "It's a very real possibility she did get cold feet. I mean, how many husbands have gone out for a pack of cigarettes and not come back?"

Belcher told FOX News in an interview Thursday that Mason was the only person who has told them that Wilbanks went jogging.

Before she left, "she talked to her mom ... about the different wedding stuff they had to get done for today," Mason said Wednesday night during an interview on FOX News' "On the Record With Greta Van Susteren."

Mason and Wilbanks, both 32, were to be married Saturday in what was expected to be a big bash, with 600 invitations sent out and 14 bridesmaids and 14 groomsmen, said Mason's mother, Vicki.

Melinda Larson, a friend of Mason's, said the guests will go to the church Saturday, either to pray for Wilbanks or to attend the wedding, if she is found. But Larson was befuddled at the lack of evidence.

"Right now there are no new leads, and it's been 48 hours. It's very baffling."

Anyone who thinks they may have seen Wilbanks is asked to call the Duluth Police Department (search) at 770-476-4151.

FOX News' Todd Connor and The Associated Press contributed to this report.