tell me about him, what kind of a man is hapilan. >> a very bold fighter. >> reporter: this man is a former islamist militant before renouncing violence and joining witness protection, he spent years in the jungle fighting alongside the man who now leads isis in the philippines. do you think he enjoying killing people? >> yes. when i spoke to him many years ago. he always think that killing non-muslims satisfy allah, makes allah happy. i was shocked. >> reporter: in the month-long battle isis has killed scores of for soldiers and wounded more. the fighting has also triggered a humanitarian crisis. more than 330,000 people have fled their homes, and hundreds of civilians are still believe