Well, what ever you do DO NOT get involved with any person trying to do any rites or ceremonies without understanding the issue. It could worsen the situation and you could have something raging around. If there is such an issue in your place it is required to be solved effectively after proper investigation and thought.

Regarding your child seeing something please dont worry. Every child is born with extra perceptions and psychic sense. As we grow older most loose this channel due to conditioning of parents and society. Your child has seen something of this sort before but never mentioned it to you for the fear of reprimand.

Anyway goodluck