if it says admin next to user name in chat then that's an admin. If aAdmin is in their username it's likely an imposter
People have really nothing to do. It is so sad that they try this. Sometimes scammers from Telegram are sending me messages with. How can i help you today sir ? They are imposters of the admins in Telegram groups.
Seriously, I wonder why people will be so wicked and jobless as to the extent of sitting to think of ways to hack an individual's account instead of actually putting such Time for thinking into good use