Authorities say the woman was supposed to share custody of her two children with their father last week, but that never happened.

40-year-old Jessica Smith was arrested Sunday after her SUV was spotted by a Coast Guard helicopter.   The search for Smith began after she went missing last Friday.  Her two daughters, ages 2 and 13, were found by a maid in a hotel room at Cannon Beach, OR.

The teen girl, Alana Smith, was suffering from severe cuts, but is expected to survive. She was airlifted to a Portland, OR hospital.  However,  2-year-old Isabella Smith was found dead in the room.  Police have not said how she died, but it's been ruled a homicide.

Alana Smith has not yet told investigators what happened in the hotel room.   Court records, according to our news partner KNDU-TV, indicated the mother was supposed to share custody of the two girls with their father, but she never dropped them off to him.  She then went missing Friday, leading to a search of the Oregon coastline.

She has been charged with murder. Smith is pictured below.

(Courtesy KNDU-TV)