A police chief said her remains were discovered a month ago in remote woodlands and her identity has now been confirmed by forensic experts.
The little girl was last seen by family members at 11 p.m. when she went to bed for the night.
Tucson police say they're announcing a development in the case of Isabel Celis, the girl who went missing from her home almost five years ago.
The remains of Isabel Celis, a six-year-old girl who went missing from her home in 2012, have been located in rural Arizona.
At the time, the case drew comparison to the disappearance of three-year-old Madeleine McCann, who vanished while on holiday with her parents in Praia da Luz, Portugal, on 3 May 2007.
Police never named any suspects, but they said they found "suspicious circumstances around a possible entry point" in the home. Magnus said Friday, March 31, 2017, that an independent lab identified the remains as those of Celis.
Isabel Celis as she appeared in 2012, when at age 6, she vanished.
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Isabel Celis disappeared from her family's home in 2012.
Tucson Police said it would not be releasing any further details an an intense investigation is ongoing. They say they are grateful the search is still on, but it was tough to look at this new picture.
The statement thanked the community for its support and the refusal to give up hope, but now, it is time for the family to grieve. "We ask for our privacy during this time so that we can do that", the statement reads.
Medical centre CEO Judy Rich said in a statement: "This is not the news we had hoped to hear".
For many years, the Celis family's house near Park Place mall still had a banner displayed with the face of Isabel pictured smiling with long, brown hair and hazel eyes.
According to KTAR, Magnus said: "This is a very important step in the case, so that's one of the reasons why we're still asking the public if they have any leads".
Magnus said the department received a tip, which lead to the discovery of the remains. "In fact, reverberations of this have gone well beyond Tucson and even Arizona, (and) have affected people throughout the country", he said.