Four bodies have been recovered so far after five persons were reported missing while bathing at Gerandi Ella in Ettampitiya.
Police said the investigations have been launched based on information received to the 119 emergency number.
A group of around 11 persons were bathing in the location when five of them were suddenly swept away by strong currents and had drowned.
It was reported that one male and four females were among the victims.
Search operations were underway to locate the missing person.