That's why when a cop asks if he can search you or your house or your car you ALWAYS respond with...

"No. I do not consent to a search. I do not consent to further questioning. I do not consent to further contact without my lawyer present."

And then you literally stop talking.

The only time you ever have to speak to a cop is if they believe you witnessed a crime. Then not talking could be considered obstruction.

They might say "YOU'RE UNDER ARREST, BUT YOU'RE UNDER ARREST" when you say you don't want to talk. That is their way of coercing you to talk. You being under arrest doesn't waive your 5th amendment rights not to talk.

So, in summary, never talk to a cop. Even when under arrest.