Terrorists next door?

me and my parents just moved in to our new house in Melbourne and our neighbours we found out are Lebanese. Could they be terrorists. I heard them speak Arab and i couldn't understand a word. apparently the couple have lived there for ten years and have had 5 kids and they have really nice stuff so could it be connected to drugs too, as i'm sure a milk bar owner can't earn that much. My dad is a professional accountant which I'm sure makes more money and we dont have that much stuff. Should i call the hotline to report them?