Detroit police are investigating the deaths of a 9-year-old and a 2-year-old, who reportedly froze to death while living in a van at Greektown Casino.

The mother and five children had been staying in the van, which ran out of gas around 1 a.m. After noticing one child wasn’t breathing, the godmother took them to the hospital, where two were pronounced dead. Three others, ages 13, 8, and 4, were unharmed.

Authorities suspect the children froze, but an autopsy will confirm the cause. The mother was detained but not arrested, and Child Protective Services is involved.

Police urge the public to report families in distress by calling 911, emphasizing that this tragedy was preventable.