Is it legal to hire police from another city?

I was hanging out in the pool area of my apartment complex in Houston (HPD) at 11 pm and a pasadena police wearing his pasadena police uniform came and asked for my id and said the pool was closed and told me to leave i asked whay he was doing if he was from pasadena and he said the complex hired the. He then wrote my name after pointing his bright flashlight at my face and asked me where i lived i told him the number then walked home. IS THIS EVEN LEGAL does pasadena have authority in houston cab they just be "hired" he WAS wearing his pasadena police uniform and using his pasadena police car