Mawkyrwat: One person identified as Sailet Kharwanniang (65) from Rangmaw village drowned in Phot Um Tyngkoh stream in Domjyrti-Rangmaw in South West Khasi Hills, on Thursday night.) According to sources, Kharwanniang is suspected to be suffering from some mental problem. ‘He left the house alone at 11 pm and went to the stream to take bath and did not return’, sources said.