Sarath Weerasekara made the news in 2017 for going to Geneva to hand-over all manner of petitions against the OHCHR head, as well as earlier in the year with dossiers. He also took it upon himself to defend war crimes allegations.
A Google search brings up this recording, allegedly between journalist Wasantha Chandrapala and Weerasekara, conducted in Sinhala. Weerasekara openly threatens Chandrapala.
Weerasekara has a dedicated website, at http://www.sarathweerasekara.com.
The site archive was taken on 14 June 2017. Download it here.