There's nothing wrong with catching tax cheats as long as due process is followed and the person's rights are not infringed. However, selective enforcement can be used as a weapon - never investigate people "on your side" and always investigate "enemies" even if there's no evidence of fraud. Another way to weaponise enforcement is to have a law that is almost never prosecuted and rarely followed (e.g. only using bare hands to eat chicken in Gainesville, Georgia), so then a law enforcement officer can threaten to prosecute for it unless the victim complies.
Another great way to do this would be to preemptively arrest your political enemies with a pretext of assumed fraud and use that as a fishing expedition. Then you could spread your retribution by trying to violently suppress anyone who got in your way and use that as a pretext to send in the army to raid some billionaires' compounds.