The former LTTE member, Selvarasa Pathmanathan, alias KP, is now "free", reports the BBC.
Speaking to the BBC the head of the Media Centre for National Security, Lakshman Hulugalle, said there was "no case" against Pathmanathan at present, and that "practically, there is no detention now".
Pathmanathan's release was explained by Hulugalle, who remarked:
"I think it's a victory for us - at one point he was against us and was a leader of Tamil people.
"Today he is working for development of this country - he is free to do that."