People always say pleading the 5th is a red flag. No. It is your right. Any lawyer worth their salt will tell you to claim the 5th on something like this. They were fishing and his lawyer allowed the FBI to just keep casting their lines. They can twist anything you say, including honest mistakes.

Edit - forgot to mention this. Because of what I did in the military I had a lot of Federal Agent friends from all branches as well as USSS and FBI. Several of them told me many times to remember 3 things.

1. I want a lawyer.
2. I do not consent to a search.
3. I wish to remain silent.

None of those can be used against you - especially in court. If a prosecutor tried to say what you said about a red flag the judge at a minimum would hammer the prosecutor and instruct the jury to disregard that statement, or at worst order a mistrial.

I wanted to edit to clarify, because statements like yours can scare potential defendants into saying things that end up convicting them.

People always say pleading the 5th is a red flag. No. It is your right. Any lawyer worth their salt will tell you to claim the 5th on something like this. They were fishing and his lawyer allowed the FBI to just keep casting their lines. They can twist anything you say, including honest mistakes.