The 82-year-old Kasem and his wife, Jean, have been staying with family friends in Kitsap County, west of Seattle.
Sheriff's officers on Wednesday delivered documents to Jean Kasem warning that her failure to appear in Kitsap County court could lead to a warrant for her arrest.
A spokesman for Kerri Kasem has said she has a Washington court order that allows her to see her father.
Earlier this month a Los Angeles Superior Court judge Daniel S. Murphy ordered Jean Kasem to comply with court orders allowing doctors to evaluate her husband, and to let his daughter Kerri see him. He also ordered Jean Kasem to surrender her husband's passport and temporarily suspended her powers to determine her husband's medical care.
In mid-May, Murphy expressed concerns about Kasem's whereabouts and safety amid a dispute between his wife and children from another marriage.
The Kitsap County Sheriff's Office tracked him down the next day. A sheriff's spokesman said those at the home, including Jean Kasem, said appropriate medical care was being provided.
Casey Kasem gained fame with his radio music countdown shows, "American Top 40" and "Casey's Top 40," and was the voice of Shaggy in the cartoon "Scooby Doo."