MONTGOMERY COUNTY, Texas -

Police are investigating what caused a three-car collision in Montgomery County involving six people and three small children.

According to investigators, a woman was driving a SUV with three kids inside across a bridge on Highway 105 at around 10 Sunday night. For unknown reasons, she swerved lanes hitting an Escalade head on.

Meanwhile, a Ford Explorer with three adults inside ran into the Escalade due to the dark roads.

Everyone involved was taken to the hospital, including four in critical condition.