Wait, wait, don't use any bot for such an account. One person in my network recently used a tool to remove followers in bulk and ended up getting their account blocked.
Removing followers also has limits, so please be careful. You can do it manually or hire a virtual assistant (VA) to do it manually for you.
To identify bot followers, you should employ certain logical techniques. Start by examining various aspects such as the profile picture, followers, posts (especially if a majority of them were posted on the same date), and the username. By thoroughly evaluating these factors, you can make a judgment on the authenticity of the account.