World 1 - The police have no right to detain you and CANNOT compel you to answer:
"I'm not answering these questions, and I'm leaving."
World 2 - The police have no right to detain you but they CAN compel your answers:
"Did you kill your stepmother", "In elaborate detail, what did you have for breakfast?", "Do you like my shoes?", "Here's Ulysses, read it and tell me what you think", "Here's a hammer, show us that you didn't hide your stepmother's head at the center of this enormous boulder?", and on and on for decades.
Forty-Two years later:
"Did you kill your stepmother?"
"Sure, whatever you want to hear, Man."