Problems with Prescious Peeing

I am so confused! My oldest (male) prescious peed on my bed this morning while I was watching him! He is 4 years old and has been using his litter box regularly since I brought him home. I suspect that he may have done this twice before. When my mother-in-law came to visit, he hated her! and one of my three peed on her bed. It happened again when my niece came to visit as well. Prescious, again, hated her. I could never prove it was him those two times, but I saw him this time. Can anyone give me any clue as to why he decided to do this on MY bed in front of me? does anyone know how to clean urin out of a bed? Thanks guys!

First thing is vet check, this is a common sign of UTI as well as possible side effect of other health issues. Once that is clear, it could be a over reactive emotional negative behavior.....Let us know after vet check, we want to help!