Isabel Mercedes Celis' disappearance from her Tucson Ariz. home this weekend is being described as an unusual case, with police saying there's no evidence she was taken from the residence or that she left on her own.
Celis' parents last saw their 6-year-old daughter Friday night around 11 p.m. in her bedroom.
When Celis' father went to wake her up on Saturday morning, she was gone.
"She was checked on at about 8 'o clock so they can start their day. And she was not in her room at that point," said Sgt. Maria Hawke of the Tucson Police Department.
Police are exploring all possibilities.
"We don't have an actual piece of evidence that points us in one direction or another so for example we don't have a piece of evidence that says she was definitively taken from the residence. We don't have any specific piece of evidence that tells us she left the residence on her own," said Hawke.
Isabel's family has no doubt she was kidnapped by a stranger.
"You don't think anything like that would actually really happen to you. And all of sudden, you wake up one morning and you're in that scenario. Everything goes through your mind, you're angry, you're upset, you're frustrated, you're confused," said Isabel's uncle and family spokesperson Justin Mastromarino.
Mastromarino said Isabel's bedroom window was open. He also said her family is a loving one.
"They're very upset right now, mother is beside herself we're just trying to let police do their thing and get as much info as possible," said Mastromarino.
Mastromarino described his niece as "just a sweet little girl."
"All the ambition in the world. She could do whatever she wanted. Didn't really like strangers or anything like that so very close knitted and just very wise," said Mastromarino.
Scores of police, FBI agents and federal marshals are engaged in a massive manhunt, which include aerial grid searches and checkpoints on the ground. They have virtually locked down the neighborhood, asking anyone if they've seen Isabel. Police have kept everyone away from the home as they look for any signs of damage or forced entry.
ABC News Radio contributed to this report.