We are any a very difficult position where our neighbours (semi detached) are an elderly lady and her son who is probably in his late 50’s with severe learning difficulties. He won’t engage or look you in the eye, is very removed and extremely sensitive to noise. He has a huge problem with children and has previously screamed at our child calling him an idiot and stupid (he is 3...) for playing on his trampoline in our garden. He has also shouted at other children playing in the street if they are in front of their house. We regularly hear him having outbursts of rage - shouting and hitting or banging furniture and can hear him calling his mother a stupid woman, or he will direct his frustrations at us for say, eating in the garden with 2 friends (before lockdown) or for my husband pressure washing the patio and shout at us calling us morons etc. He sometimes sounds like he might come through the wall. Until he directed his anger at our child, we turned a blind eye, but did have a word with his mother when he shouted at our son and she was somewhat sympathetic and said he doesn’t understand. We have no reason to believe he is violent with her, he just has rages over things that must trigger him. Recently things took a turn as he left a menacing letter on our car windscreen directed at my husband and son saying he would damage our property and he was fed up with our son making noise. The note was written on a typewriter, fairly repetitive, erratic and hand written in places and very unnerving. I can hand on heart say our son is very loving, sweet and no noisier than any other young child. He is also out most days at nursery. We called the police about the letter and he has had a warning, but I feel sick to my stomach, fear he may do something to us, our son or our property. I also feel deeply unnerved about the fact this is an issue with mental illness for which I hold a lot of sympathy. I’m so teary and confused with emotion but ultimately must safeguard my son. Has anyone had anything similar or can offer some words of support? The police have been amazing so far and said to record any other incidences but as they are erratic and unprovoked it is very hard to film at the right time etc.