Interrogation isn't always bright lights and rubber hoses—usually it's just a conversation. Whenever law enforcement officers ask you anything besides your name and address, it's legally safest to say: "I am going to remain silent. I want to see a lawyer."
This invokes legal rights, which protect you from interrogation. When you say this, the officers (and all other law enforcement officials) are legally required to stop asking you questions. They probably won't stop, so just repeat the Magic Words or remain silent until they catch on. If you forget your decision to remain silent and start talking to law enforcement officers, you can and should re-invoke the Magic Words, then remain silent. Do not raise your status as a medical cannabis patient, unless you are specifically asked about this or the medicine has already been found.
Remember, anything you say to the authorities can and will be used against you and your friends in court. There's no way to predict what information law enforcement officers might try to use or how they will use it. Plus, law enforcement officers often misquote or lie altogether about what was said. So say only the Magic Words and let all the law enforcement officers and witnesses know that this is your policy. Make sure that when you're arrested with other people, everyone knows the Magic Words and promises to use them.
One of the jobs of law enforcement officers is to get information out of people. Law enforcement officers are legally allowed to lie when they're investigating, and they are trained to be manipulative. The only thing you should say to law enforcement officers, other than identifying yourself, are the Magic Words: "I am going to remain silent. I want to see a lawyer."
Here are some lies they may tell you:
"You're not a suspect -- just help us understand what happened here and then you can go."
"If you don't answer my questions, I'll have no choice but to arrest you. Do you want to go to jail?"
"If you don't answer my questions, I'm going to charge you with resisting arrest."
"All of your friends have cooperated and we let them go home. You're the only one left."
Law enforcement officers are sneaky and there are lots of ways they can trick you into talking. Here are some scams they may pull:
Good Cop/ Bad Cop: Bad cop is aggressive and menacing while good cop is nice, friendly, and familiar (usually good cop is the same race and gender as you). The idea is bad cop scares you so badly you are desperately looking for a friend. Good cop is that friend. The Bad Cop usually questions you first, pretends to give up or take a break with you, and then the Good Cop enters to sympathize with you about how much of a jerk the other guy was. It is in this "friendly" conversation that the Good Cop will be looking for any information or a confession.
Prisoners' Dilemma: The officers will tell you that your friends ratted on you so that you will snitch on them. Meanwhile, they tell your friends the same thing. If anyone breaks down and talks, you all go down.
Law enforcement officers will tell you that they have all the evidence they need to convict you, but that if you "take responsibility" and confess, the judge will be impressed by your honesty and go easy on you. What they really mean is: "We don't have enough evidence yet, please confess."
Jail is a very isolating and intimidating place. It is really easy to believe what law enforcement officers tell you. Insist on speaking with a lawyer before you answer any questions or sign anything.