My DS almost 4 went through a period few months back after they had visits from the police and fire fighters at his preschool... he was freaked out that if he was bad that the police would get him and that when he saw fire (like from the stove) that the house would burn down and he's tart crying and get down low and crawl to the door.... I thought it was something from the TV til i saw pics up at preschool and asked them and found out that an older boy had asked the plice what they do with Bad people... And the fire fighters talked about what to do in a fire...

Also our dog when we moved house got a bad case of fleas...we think the previous owners pets had them... grrrrr.... Anyways i get bad reactions to the dog (from the fleas... i told him that they were little nits and he freaked out for weeks after that things were biting him in his bed (after i treated the dog's bed) Once i treated his bed (washed his sheets with his help) he calmed down. I find the smallest of things cause triggers