I am a movie director and I just received the following movie plot. Could you help me answer this question? If not, let me know by writing "Not answerable". Plot title: Elite Squad Movie plot: Captain Roberto Nascimento (Wagner Moura) narrates the film, briefly explaining how the police and the drug lords of Rio de Janeiro cooperate with each other (policemen collect periodic bribes and drug lords are left free to operate) in the 90's.In 1997, In medias res, officer Captain Oliveira (Marcelo Valle) and his colleagues are shown driving through Morro da Babilonia towards a baile funk. Nascimento and his other colleagues are also shown in their armored car. Meanwhile, novice police officers Andre Matias (Andre Ramiro) and Neto Gouveia (Caio Junqueira) are shown riding a motorcycle at the same favela, though not with the other officers. Once they make it to a vantage point, Neto uses the telescope of a sniper rifle to check on the police team as they talk to some drug traffickers. Neto shoots one of them and provokes a deadly gunfight between police and thugs, both sides unaware of where the bullet came from, forcing Mathias and Neto to flee the scene. Nascimento leads his colleagues from BOPE, Rio Special Police Department, heading to the shootout to interfere and save the officers.Six months earlier, Nascimento and his wife Rosane (Maria Ribeiro) are shown during her pregnancy of their first child. Not wanting to be an absent father when his child is born, Nascimento decides to search for a successor for his role as a captain, since he will be promoted to Lieutenant Colonel. This coincides with an operation he will have to lead at Morro dos Prazeres in order to secure the location and clean it of drug dealers, so that Pope John Paul II can spend the night in Archbishop's home, located near the slum buildings and favelas. The operation will require daily trips into the favela filled with heavily armed drug lords, and Nascimento is initially against it, but is forced by his superiors to accept it as his last mission, due to Pope's regards and requirements which cannot be annulled.Meanwhile, Neto and Matias debut as police officers. Both are honest and try to stay out of corruption, but are soon... My question: Why did the drug lord decide to take revenge on Matias?
Answer:
For killing his friend