Police believe they may already have interviewed a suspect in the kidnapping of 14-year-old Elizabeth Smart, who was taken from her home at gunpoint last week.

"We believe that it is possible that we have already talked to or will soon talk to the suspect that is responsible for this crime," Police Chief Rick Dinse said on Tuesday.

"We do not have a name pegged to that person," he said.

He said the investigation was headed toward focusing on someone who had access to the neighborhood or the house, although not necessarily a family member. He said they have received some promising leads in the case.

"We don't have an identified suspect but we do have some analysis of what this suspect is like," Dinse said.

"To the person that has taken her, understand this:

"We will get you. We will get you. If you have her, you have better release her right now."

Forensic investigators spent several hours in the missing girl's home early Tuesday morning, searching for clues to her apparent kidnapping at gunpoint a week ago.

The investigators left the sprawling million-dollar home at 3 a.m., police said.

Seven days after the 14-year-old was abducted from the bedroom she shares with her sister, police said they have ruled out the possibility that the girl staged her own abduction and was a runaway. They did not say why they had ruled out those possibilities.

The search of the home came after Ed Smart, Elizabeth's father, submitted to a polygraph test on Sunday. The test is being evaluated by the FBI.

"It's just one of the tools we've been using to further the investigation," police Capt. Scott Atkinson said. "We're looking at every possible angle."

Police would not say what questions were asked and a family spokesman did not know whether Smart had an attorney present during the questioning. Police did say other family members may be tested.

In a statement released Monday evening, Smart said, "When asked by law enforcement I fully cooperated because I have nothing to hide. We are doing everything in our power to bring back Elizabeth."

Police also they going to re-interview 9-year-old Mary Katherine Smart, who had told investigators that a gunman came the bedroom she shared with her older sister and forced her to go with him. She said he told her that her sister would be hurt if she told anyone. Police said it was at least two hours before she woke her parents and told them.

"It's not uncommon" for police to give polygraph tests to parents, or to do several interviews, police Detective Jay Rhodes.

Atkinson said 40 FBI agents and 60 police investigators continued to sift through the thousands of tips, but, "At this point, we're no closer to solving her disappearance."

The volunteer search through the city and mountain foothills was tapering off. On the first day of the search, 1,200 people volunteered to find Elizabeth. By Monday morning that number had dwindled to 400.

However, the search also is expanding into other areas.

Tom Smart, one of Elizabeth's uncles, asked for 40 or 50 all-terrain vehicle owners to help search the West Desert area.

Chris Thomas, a spokesman for the family, said 55 ATV owners turned out, each searching a 25 square mile area.

He said the ATV search would be continued Tuesday and there also were discussions about holding a four-wheel-drive search in the mountains and enrolling horse posses.

Rhodes said the volunteer search effort was unprecedented in Utah, with volunteers flying in from the East Coast and calls coming from Italy and Germany. He speculated that the 2002 Olympics made the city familiar worldwide.

Interest in the abduction and the search "blossomed because during the Olympics Salt Lake City became America's hometown, kind of like midvalley America," Rhodes said. "Now all of the sudden you have someone invading midvalley America and taking someone from their bedroom."

The Associated Press contributed to this report.