A foreign-manufactured revolver and 12 live rounds of ammunition have been seized from a house in Mattakkuliya, police said.
The weapon and ammunition were recovered on Wednesday on information obtained from a suspect currently held at the Colombo Crime Division under a detention order.
Suspect brought to Sri Lanka from overseas
Police said the suspect had been brought into the country from overseas and is being detained while investigations continue. Officers searched his residence in Mattakkuliya on the basis of information he revealed during questioning, and recovered the revolver and the 12 rounds there.
The Colombo Crime Division is conducting further investigations into the incident. Police did not identify the suspect, state the charges under investigation, or say where he had been brought back from.
Mattakkuliya, a densely populated area in northern Colombo, has featured in a series of recent organised crime investigations, including an abduction and murder case in which the Special Task Force made five arrests.