TUCSON, AZ (Tucson News Now) - Unfortunately, reports of missing children aren't that uncommon.
Between runaways, breakdowns in communication or kids just staying out past their curfews -- there are far more reports than actual cases.
But from the very beginning, the Isabel Celis case was different.
"The first call I got about this was from the division captain," says Roberto Villaseñor, chief of the Tucson Police Department. "And his first words were almost, 'This one feels legitimate.'"
Saturday morning, April 21 -- the father of Isabel Celis realizes his six-year-old daughter is not in her bedroom.
He says he put her to bed at 11 p.m. the night before.
But when the family gets up at 8 the next morning, little Isabel is gone -- and 911 is called immediately.
Within the hour investigators converge on the family's midtown home.
At first glance, it appears somebody had removed the screen from Isabel's bedroom window, a window only about 20 feet away from the house next door.
"It's directly over this wall, right there," says Alicia Stardevant, pointing at Isabel's bedroom window. "And that's my bedroom window right there."
What's interesting about this particular neighbor is that Stardevant says she heard men's voices around 6:30 that Saturday morning.
The sun was already up so she didn't really think anything of it.
That is, until Isabel's uncle frantically pounded on her door about an hour and a half later.
"He asked me if I've seen a little girl around here -- and I said no. He said his niece was missing."
That's when Stardevant starting putting two and two together. Men's voices outside her bedroom window and a missing little girl -- could they be related?
"I didn't hear her ... I never heard her voice," Stardevant says. "I heard a couple of male voices right outside my bedroom window, right outside her bedroom window But I didn't hear a struggle. There was no fighting and I think she was taken by someone she knew."
It was around that time we first started hearing about a possible abduction, as national media and the centers for missing and exploited children set their sights on Tucson.
Later that afternoon upwards of 250 officers saturated the neighborhood near Broadway and Craycroft.
Within 24 hours FBI search dogs were flown in from Virginia.
24 hours after that behavioral analysts from the FBI arrived to observe the missing girl's family.
During this time Tucson police extended their search to Los Reales landfill.
For two days, investigators sifted through trash and debris looking for anything that could be associated with the girl's disappearance.
Through bone-dry conditions and temperatures approaching 100 degrees, authorities found nothing.
That's a synopsis of first 72 hours.
Since then, we've seen more than a thousand tips come in and some $50,000 generated in reward money.
Go to any store or restaurant in Tucson and you're bound to hear an opinion.
"I've heard speculations that the family is involved in drugs, the cartel," Stardevant said. "But that's just what people are saying. Who really knows?"
"We've been examining every possibility, whether it be extended family members, friends," Tucson police Sgt. Maria Hawke said. "We haven't ruled out anyone."
Regardless of all the theories and speculation, this all boils down to a nine-hour window between that Friday night (April 20) and the following Saturday morning.
What exactly took place in the Celis home that night? And did it involve somebody from inside or outside of their house?
That, essentially, is the million dollar question.
Who is responsible for the disappearance of Isabel Celis?
Was it an intruder who snatched up the little girl and took her away?
Or was it a member of her own family as we asked her parents in an interview last week.
"I really don't know what to answer to that because other than, you're wrong," said Sergio Celis, the missing girl's father.
"Say what you want to say, but in the end we are confident that we had nothing to do with it," Isabel's mother Becky Celis said. "Go ahead, go for it. The people who know us, who've known us as a family know us -- and (they) know that we have nothing to do with it."
We asked a nationally renowned body language expert what he took away from the Sergio and Becky's response.
"That's a little bit of an inconsistency as to what we'd expect to see."
Aaron Brehove is a senior body language instructor at the Body Language Institute in Washington DC.
His background is in detecting deception. He says Becky Celis' use of language was rather peculiar when she said she's confident her family had nothing to do with Isabel's disappearance.
"Instead of saying we're confident we had nothing to do with it -- I would expect her to say we have nothing to do with it," Brehove said.
Villaseñor wouldn't discuss specifics about what Sergio and Becky Celis had to say.
But he did tell us his agency, the FBI and US Marshals have made significant progress over the last 20 days.
"The reality of the situation is that we still could go a couple of different ways with this investigation," Villaseñor said.
When you consider all that's happened over the last three weeks, all the time and energy and resources (more than $1 million to date) invested into this case -- this is very big news.
Investigators are narrowing everything down to a couple of working premises, Villaseñor said.
Even though the chief is very measured in what he has to say, this is the first time he's really suggested a possible tipping point in the Celis investigation.
"The detectives who've been working it have gone back over interviews. They've talked to people several times. They just need that one break that's gonna tie things together that they're suspecting," Villaseñor said.