CASTLE PINES NORTH, Colo. -- The investigation into the deaths of two young children in Castle Pines North is in a holding pattern while detectives wait to find out how they died, Douglas County Deputy Cocha Heyden said.

Deputies found 5-year-old Jasmine Mendieta and her 2-year-old brother, Nathan, inside their mother's car outside their home on Bramblewood Drive. Deputies had been called to the home Wednesday afternoon on the report of two missing children.

Within minutes of searching, deputies found the children inside their mother's red Honda Civic. The automatic windows were rolled up. Jasmine was on the floor in the front passenger side and Nathan was on the floor in the back, according to the children's grandfather, Ken Vanherpen.

He and many others wonder how a 5-year-old girl couldn't get out of a car, if she had been accidentally locked inside.

Dona Aldrich, a family friend and neighbor, said the children lived in their grandparents' home with their mother.

Neighbors said the mother, Stacey Mendieta, 28, had recently gotten a divorce and quit her job, but that the children's father had not been in the picture for months.

Mendieta was alone with her kids when she reported them missing, Vanherpen. Family members told 7NEWS that Mendieta was planning to leave the country to meet up with a man she had met online.

The home is still surrounded by crime tape, as detectives piece together clues and interview family members and neighbors.

"That's really important, because if we can establish a timeline, maybe see how long the kids were in the car, when they got in, if someone saw them get in, any information that someone has that they haven't told us, we'll take it," Heyden said.

Douglas County deputies said the coroner's office could release a preliminary cause of death for both kids as soon as Friday and that will help determine the direction of the investigation -- whether it will be a criminal investigation or an accident investigation.

Meanwhile, neighbors in the close-knit community are organizing a meeting for Saturday morning to raise money, organize dinners and rally around the family. They have also set up a fund in the children's names.