She drove around for an hour before doing anything at all about the situation. At a minimum wouldn't you rush your children to the nearest hospital to try to revive them hoping there was a chance? This alone is very much a like a hit and run. At no point during this whole episode did she show any concern for the children. Everything was about her alone.
But according to the information in the story, there is not sufficient evidence for murder; the deaths, if proven well enough to have at least been caused by negligence, by state law, probably affects a charge of manslaughter.