Not worked for police but worked on and off for years on side as insurance investigator. Fake claims, fraudulent claims etc. (family business) - that is why tone, text, manner, personalities, commonalities don't often get past me. It's also why I have the belief I've already stated.
Often if a fake persona is proven, a new one appear in short time. Cheats are always cheats. Fraudulent claimants tend to have pattern of dishonest schemes. Liars are always liars. But mixed in with lies, the true person has traits that show through. When caught, if the clues are shared, next time round, those give away clues are addressed.
But underlying personal traits (victim mentality, the blame game (everyone else is odd/rude/disrespectful), pity votes, condescending tone, need for centre of attention) all are pattern they can't escape.
This is those who investigating don't release all the information. There are always traits/clues which aren't disclosed.
If you call someone out on being fake, and tell them why and then same fake/scam/scheme pops up and only the clues you shared are changed but the other tell-tale signs not changed, then it often easier to spot. Also, you get to see the common behaviours.
I have my beliefs and reasons for holding them. Someone crying "unfair" is not going to change my mind because liars lie and it's about deflecting attention. The normal way of doing the is to try and turn attention back on accuser.
Everyone who ever had a teen knows this.