Fight with person living in same building

I had a fight with a person in my building who has been harrassing me since past 3 years. He blocked my way while i was going to office and bumped my car and was not allowing me to go to office On heated verbal discussion, he gave me very bad words on mother and refered to the harassments he was doing from past 3 years. I lost my temper and had hand 2 hand fight. He came to attack me so i used my belt for self defense. Police was called and we went to police station, there he brought the cctv footage of fight. I told the police what I have been going through and what has happened. The police asked us to say sorry to each other and the issue was settled. After 6 months he sent complain letters to police higher authorities with CCTV footage. I was called again to police station. Again explained what has happened and police took written statement from both of us that we will not fight again and the matter was closed. This person is very unreliable and has been trying to harass me since past 3 years He is not even the member of society but comes and bully members and intimidates members. I just want to check, is the matter should be closed now or still this person can harass me going to other authorities. Incase he does this, what can I do to protect myself from this kind of harassments Please note, This person sends anonymous messages on mail defaming me to all members. He know the mails cannot be tracked and gets away. Then he comes in meetings and tons on the defamation messages he sent. Please advice how a honest and simple citizen like me can protect themselves from these criminal minded people. Thanks in Advance