DES MOINES, Iowa (AP) — At least four Iowa children have died in the past 18 months at day care centers that had been warned about caring for too many children.

The Des Moines Register reports that criminal charges have been filed in two of the deaths, and prosecutors are considering charges in a third case.

Often, state or local officials know about providers that are caring for too many children, but don’t tell prosecutors or take other action to stop them.

The state has 4,300 regulated day care centers, but home day cares are not regulated.