It started 2 years ago when my sister met her boyfriend, and he met me he has started to hate me because of his jealousy of me, because I am skinnier than him and I am more intelligent. He assumes that I am rich and didn't have to work for what I have. He is obese and is 150kg+, and is very arrogant and feels like he is better than others. He finds it difficult to keep jobs for some reason. He works as a metal worker. He is very good at appearing charming and telling people exactly what they want to hear. He tries to seem like a decent person as much as possible to other people. When he gets drunk then he starts swearing, being very racist towards black people, and being very misogynistic, in other words his true nature appears. But he pretends to be a good person and always tells stories where he portrays himself in a good light. You can never tell from his facial expression whether he is angry with you when he is around other people. He is nice to others but looks at me with hate. My gut feeling when I see him is that he looks like a dangerous person. He looks like a ex con. He started putting something on my toothbrush, and in my toothpaste every time he would come over and would go to the toilet that gave a burning sensation in the mouth and tasted like chemicals. I left a note next to my toothbrush/paste saying I know that you have been messing with my toothbrush and toothpaste and if you do it again you will know what it's like to pick up your teeth with broken fingers. Then, the next time he came over he rubbed shit on my toothbrush. So I got sick of him messing with my toothbrush and paste and put both in a lock box. The next time I opened the box with a key, there was poop on my toothbrush again. So I moved my toothbrush and toothpaste in my room. Then he started messing with my bottled water, and wiping his ass on my shower towel. After drinking from the water I got a stomach ache, had a tingling sensation in my hands and feet, and felt weak. So I bought a security camera and pointed it in the direction of the water and my room. But that didn't deter him and he messed with the water and, he went inside my bedroom and put something on my toothbrush again. Because I had the same burning in my mouth when brushing my teeth with the toothpaste and a stomach ache after drinking the water. He put something in my toothpaste recently that when I held it up to my nose it smelled like petrol. I don't know what to do now. He is obviously trying to get on my nerves and make me sick. He might be trying kill me.