Authorities continued to sift clues Tuesday after a fire broke out Monday at a group home in Missouri Ozarks, killing nine residents and one staff member. Eighteen other people were hospitalized, some in critical condition.

Gov. Matt Blunt (R), who visited the scene at the Anderson Guest House, said the fire was suspicious. Joplin River of Life Ministries Inc. operated the one-story home for the mentally ill and disabled. State officials said the facility passed state inspections as of March.

There were no sprinklers in the facility and it is unclear if the smoke alarm system worked, said state fire marshal, Randy L. Cole. The Centers for Medicare & Medicaid Services last month proposed that all nursing homes be equipped with sprinkler systems. This facility, however, because it is a group home, is not subject to the same federal oversight.