A tenant of a landlord is harassing me. What can I do?

The landlord rents to two brothers. The front house brother is harassing me. The latest event was when I was inspecting my fence damage his brother in the back house may have done he drove his motorcycle up behind me and sideswiped the back of my leg (my brother was also sideswiped). I didn’t suffer any injury. I am terrified to call police or get a restraining order for fear of retaliation. He has beaten up his brother’s kid in the back in a horrific rage. He is also a 2 strike felon. The brother in the back had his adult kids try to attack neighbors across the street with weapons. One was arrested on a felony weapons charge. The back brother and children blatantly smoke pot and meth on the driveway in clear view of others. Other neighbors are afraid also and don’t want to get involved. Everyone is afraid to call the police on them. The landlord thinks I am lying about the situation and won’t even check with the police dept. for information on the latest incident with brother in the back when someone finally called the police. He is afraid to lose rent. What can I do? They are turning our neighborhood into a gang banging drug haven. Is there any way to hold the landlord liable in this situation?