LINCOLN, Maine (AP) Maine State Police say a woman who was standing outside of her parked vehicle on Interstate 95 was killed and her toddler son critically injured when a tractor-trailer struck them.

Police say the crash happened Thursday afternoon near Lincoln. Police say the woman’s car was parked in the breakdown lane. Authorities say the victim was standing in the travel lane, holding her son, when she was struck.

The woman’s son was taken to Eastern Maine Medical Center in Bangor.

Maine State Police are investigating the crash and believe it was a suicide.