TEXHOMA, OKLA. ? An autopsy has found smothering was the likely cause of death of a 5-year-old Kansas girl whose body was found in a Texhoma, Okla., motel after her mother was hit and killed by a train.

The body of Alexandria Leigh Warner, of Topeka, was found Oct. 30 after her mother — Rose Warner — was killed after walking into the path of a train. The Oklahoman reports that the autopsy said drugs used to treat anxiety were found in the child’s blood.

The same drugs were found in Rose Warner’s system. The medical examiner found that Rose Warner died of multiple blunt force trauma but could not determine whether the manner of death was homicide or suicide.

Authorities say the two had checked into the motel after their car broke down.