From where can we learn about the UNP para-militaries like PRRA and their attrocities against Sinhalese youth ?

What are the famous Paramilitaries exsisted during 87-89 under state sponsorship?

What are the crimes they commited against Sinhalese youth?

Who are the leaders of those Paramilitaries and what do they do now? ( I heard Rajitha Senarathna operated one unit, but I'm not sure)

What are the crimes those Paramilitaries commited against the rest of Sri Lankans( Tamils and Muslims)

What were the political games they played? (Like killing people and framing JVP)

And finally where can we learn more of them?