Being Questioned by the Police and Unrelated Crimes

[UltraVires]

@glee

Cop: “Thank you for coming in Mr. Glee. Now you saw the bank robbers leave and run to their car?”
Glee: “Yes, I gave a full description to the officer at the scene - and I noted the license plate.”
Cop: “We really appreciate all that and it will help the investigation. Now we do need to know how accurate you are as an eye-witness. Because you could be called upon to testify in court and the defence will ask you questions.”
Glee: “I understand. Well I’m 52 years old and wear glasses, but the prescription is only 2 years old.”

time passes …

Cop: “OK, Mr. Glee. We now know you are 54 and last got a prescription 3 years ago. YOU ARE UNDER ARREST!”
Glee: " :eek: "

Or how about this:

Cop: How are you today, Mr. Glee?
Glee: Fine, thank you.
Cop: We happen to know that you have a bit of a cold today. You’re under arrest.

[Cervaise]

glee: “Knock knock.”
cop: “Who’s there?”
glee: “Orange.”
cop: “You have the right to remain silent.”

[Garula]

Okay, time for a bit of a wacky hypothetical.

Suppose a serious crime takes place and I witness it. However, I witness it because I’m committing some other nefarious, though much lesser, act in the vicinity. The police talk to me and somehow they infer that this is the case, even though I haven’t said anything incriminating and they have no direct evidence. They don’t really care about my crime, they just want my info so they say “Alright, here’s what we’ll do. We will arrest you, but ‘forget’ to properly Mirandize you. Anything you tell us we won’t be able to use against you.” Could they do this to, in effect, guarantee me immunity?

[mks57]

@Garula

They don’t really care about my crime, they just want my info so they say “Alright, here’s what we’ll do. We will arrest you, but ‘forget’ to properly Mirandize you. Anything you tell us we won’t be able to use against you.” Could they do this to, in effect, guarantee me immunity?

That’s assuming that they wont lie about it later in court.

[glee]

@Garula

Okay, time for a bit of a wacky hypothetical.

Suppose a serious crime takes place and I witness it. However, I witness it because I’m committing some other nefarious, though much lesser, act in the vicinity. The police talk to me and somehow they infer that this is the case, even though I haven’t said anything incriminating and they have no direct evidence. They don’t really care about my crime, they just want my info so they say “Alright, here’s what we’ll do. We will arrest you, but ‘forget’ to properly Mirandize you. Anything you tell us we won’t be able to use against you.” Could they do this to, in effect, guarantee me immunity?

Based on my extensive knowledge* of US Law, I can tell you that the detectives will get a telling-off for incompetency, which would probably outweigh solving the case.
Also a defence attorney could claim to the jury that there was a conspiracy. You make up false testimony and they arrange to let you off a crime.

*I have watched many ‘Law and Order’ episodes