QUOTE (Texsox @ Sep 17, 2008 -> 09:40 PM)
I'm not so certain of your assertion that if someone else is committing a crime, and your crime is discovered that you can't be charged. Let's say for example you are trespassing down a country road and see a crime, certainly you can, and should, report it. Another example that comes to mind, an underage person in a bar. The minor gets busted, and in a separate crime, the bartender gets arrested. Or perhaps a peeping Tom who sees a crime. Of course it is different if it is the police who are breaking the law, but private individuals, I don't think so.
This is correct. The constitutional prohibitions against unreasonable search and seizure etc. apply to governmental actors (police, etc.) only, not to private entities or individual citizens (unless, of course, such parties are encouraged or enlisted by the police to indirectly do what the police could not properly do themselves).
In a criminal prosecution, the government is not compelled to ignore otherwise valid evidence just because a neutral, private party obtained it "illegally." "Unlawful" doesn't necessarrily mean "unconstitutional," which is the key matter here.
The rules are different in civil cases, however. I can't bug your house and use the illegally recorded conversations against you in court. If I hear you planning terrorism, however, that information can be used to send you to jail.