The group has been severely weakened in recent years after hundreds of its members were arrested and police seized several weapons stashes .
The group has killed more than 800 people over several decades and declared a permanent ceasefire six years ago .
The group , which has killed more than 800 people over several decades and declared a permanent ceasefire six years ago , has been severely weakened in recent years after hundreds of its members were arrested and police seized several weapons stashes .