Unless you initiate the contact with LEOs you tell them 3 short affirmative statements. Go Away, Leave Me Alone, I Do Not Want To Talk To You.
Then tell them, I am leaving. If I cannot leave, Get Me An Attorney, I choose to remain silent.
Then try to leave. But follow instructions if they object. And repeat it all.
Never had a client that worked out worse for when I was defending. Had lots who had worse things happen when they did not sit down and STFU!!!
Nemo