Is evidence obtained under false pretences admissable in a criminal trial? Is evidence obtained under false pretences admissable in a criminal trial? For example, imagine a policeman impersonates a computer technician to gain admittance to the suspect's home in order to "fix" the suspect's computer and in the course of doing this sees incriminating data. Can the policeman testify in court against the suspect as to what he saw on the computer?
Yes and no. Using deception to get someone to open the door so that you can execute a warrant is okay (United States v. Contreras-Ceballos, 999 F.2d 432). Leading a criminal to believe that you are a crime-customer (e.g. for purposes of a drug sale) and not a police officer is okay (Lewis v. United States, 385 U.S. 206), but must be limited to the purposes contemplated by the suspect and cannot turn into a general search. Lying about whether you have a warrant is not okay (Bumper v. North Carolina, 391 U.S. 543, Hadley v. Williams, 368 F.3d 747), nor is it okay to lie about the scope of a warrant (United States v. Dichiarinte, 445 F.2d 126). Misrepresenting the true purpose of entry, even when the person is identified as a government agent, negates consent (US v. Bosse, 898 F. 2d 113; United States v. Phillips, 497 F.2d 1131; United States v. Tweel, 550 F.2d 297). However, there is no requirement to be fully forthright (US v. Briley, 726 F.2d 1301) so you can gain entry saying that you "have a matter to discuss with X" even when the intent is to arrest X. In a case similar to what you describe, United States v. Wei Seng Phua, 100 F.Supp.3d 1040, FBI agents disrupted internet access and then posed as repairmen to gain access to the computer. Their efforts were wasted, as fruits of the poisonous tree.
It's generally correct in the American system that everything not forbidden is permitted. But the law you're looking at isn't really an exception. You have the legal right to tamper with evidence if tampering is not illegal, but this statute makes it illegal. The language you've highlighted merely says that the law does not apply to those who have some other affirmative grant of authority to do so. So if you stab someone to death in your kitchen, you can't remove the body or other evidence, but the detectives investigating the case can, because they have the legal authority to process the scene and maintain the evidence for trial. So the law is similar to the &quot;speaking in public&quot; hypothetical, but that doesn't make it meaningless. Because of the First Amendment, that law doesn't actually outlaw anything, but the tampering law faces no such legal barriers. You had the right to tamper until the government said you didn't. Now that it says you don't, you can only do it on the government's terms, which require an affirmative grant of authority.
In your example, there is nothing that indicates to me that there is a "particularized and objective basis for suspecting the particular person stopped of . . . criminal activity". If you have described the totalilty of the circumstances, the officer does not have the right to arrest or detain the individual. To your broader question about how specific descriptions must be in order to provide a basis for a stop, the assessment is based on the "totality of the circumstances". For example, an anonymous tip that "a woman would drive from a particular apartment building to a particular motel in a brown Plymouth station wagon with a broken right tail light [carrying cocaine]" was enough to warrant a stop. Alabama v. White, 496 U.S. 325 (1990)1 In contrast, the court "determined that no reasonable suspicion arose from a bare-bones tip that a young black male in a plaid shirt standing at a bus stop was carrying a gun." Florida v. J. L., 529 U. S. 266 (2000) The “reasonable suspicion” necessary to justify such a stop “is dependent upon both the content of information possessed by police and its degree of reliability.” Navarette v. California 572 U.S. ___ (2014) In any case, a crime must be part of the particularized suspicion. 1. This case focused on the indicia of reliability necessary for an anonymous tip to support a reasonable suspicion, but it is also an example of a degree of non-specificity in identification of a suspect.
Parties may only call witnesses for the purpose of adducing* admissible evidence. Evidence is only admissible if it is relevant. If a witness cannot give any relevant evidence, then a party has no right to call them or invoke the court's power to compel them to give evidence. In practice, if there were any doubt about the witness's ability to give relevant evidence, it is likely that the court would allow the defendant to call the witness, if only for the purpose of a preliminary hearing where the parties can argue about whether the proposed evidence is actually admissible. If a judge or juror is able to give relevant evidence about a case, they should recuse themselves. If a judge does not recuse, or does not permit the defendant to call some other witness having decided that the witness could not give relevant evidence, these decisions can be reviewed on appeal. The standard required to overturn the judge's decision varies depending on the jurisdiction, but generally the defendant would have to show that the evidence they were not permitted to adduce was also material. This might prevent a mistrial from occurring in cases where, for example, the defendant was not permitted to call the President to give evidence about something that occurred at a public event the President attended. The President's knowledge of the event might be technically admissible, but plainly not likely to advance either side of the case, given the other evidence available. Of course, if the President can give relevant, admissible and material evidence about a fact in issue then the defendant would be entitled to call them. *Adduce: cite as evidence.
It most likely can be used (there is no "fruit of the poisonous tree" doctrine). Drawing on this analysis (I can't locate Nytt juridiskt arkiv 1986 online). (Rättegångsbalken, SFS 1942:740) Chapter 35 Section 1 (35 Kap.) allows free "sifting, submission, evaluation" of evidence. Evidence can be rejected as insignificant. Specifically (following the analysis paper), The Swedish legal system does not prescribe that it is forbidden to present an item of evidence which the party has got hold of while breaking the law. Neither is the court prevented from ascribing such a proof a great value. In one instance, blood was illegally drawn (only a doctor or registered nurse may legally draw blood). The Supreme Court ruled that The fact that the blood sample was drawn by a laboratory assistant does not imply such a divergence from the Code of Judicial Procedure that it can be seen as a violation of the Instrument of Government Chapter 2 Section 6. Neither has any of the Swedish fundamental principle of law been set aside in a way that prevents the submission of the blood sample. "Surplus information" obtained by coercive means can also be used as evidence (i.e. information obtained incidentally, not related to the crime in question). Some limitations seem to have been recently imposed, taking the form on tightening warrant requirements and data retention.
Yes, why not? It happens all the time. Usually the witness will just say, "I am not sure" or "I don't remember, exactly". Also, if Bob is the only witness, how would anyone prove that he was committing "perjury"? In the case of an uncooperative or dissimulating witness, Judges sometimes can hold them in contempt of court, but it is pretty rare. In general, the court has to find "beyond a reasonable doubt" that the witness is refusing to testify honestly. (See "Federal Grand Jury Practice and Procedure" by Paul Diamond) It depends very much on the situation. Note that just trying to act "drunk" would not be a good idea, because that is contempt of court.
I will address only the legal issues. Prosecutors for very good public policy reasons are not required to prosecute every crime they have suspicions about. When exercising this discretion they consider: Is the act, in fact, criminal - many of the things you list, while reprehensible, unethical, and possibly immoral are not actually criminal. Do they have the resources (time, staff, money) to collect the evidence and run this case as opposed to the thousands of other crimes out there. There are always more crimes than can be prosecuted and these have to be prioritised in some way. Do they have enough evidence to gain a conviction beyond reasonable doubt. People can be fired or resign on suspicion, they can't be convicted on it.
Unless there is enough evidence to convict one or more of the suspects, none will be convicted. In general the argument: We know it must be one of you, but we don't know whch, so we find you all guilty. is not allowed in any non-dictatorial jurisdiction. Just how much evidence is needed for a conviction varies by jurisdiction in theory, and by judge or jury in practice. Also, it would be possible to charge several of the residents with having acted jointly in the crime, but there would still need to be sufficient evidence against each defendant to obtain a conviction.