I acknowledged Wikipedia might not be the best source, but it is the best source I could find in this case (all other sites that show up are either anti-Pak or pro-Pak propaganda sites when you Google), unless you can prove me wrong with an article from the Wall Street Journal or something?
You tell me why hasnt he been hanged in 23 odd years if he there isnt a lingering doubt about his innocence?
What radical organization did he work for? Who were his co-conspirators? The last Sikh radical organization that existed in Indian Punjab was the Khalistani organization in 1980s, and they were mostly concerned with fighting for seperatism from the Indian Govt.
While you could argue that the eventual aim of the Kahlistanis was to return to Ranjit Singhs Khalsa empire (which also includes large parts of Pak Punjab and Sindh), and some of them might have been involved in anti-Pak activities, still does not make sense because the Khalistani movement died out in the mid 80s.