Could evidence obtained through time travel be admitted under the Fourth Amendment? This is of course a wild hypothetical question and there is probably no good answer. Suppose a police force obtained a time machine and wanted to use this to obtain evidence to investigate crimes and convict criminals. Would they be able to use this evidence in court? I am thinking about a few ways the time-travelers might obtain potentially tainted evidence: The officers have obtained a search warrant to search a certain place, perhaps a suspected hideout that a suspect may have used in the course of planning or committing the crime. Currently, there is nothing incriminating in the hideout, but the officers use their time machine to go back to a time, before the warrant was issued, and find incriminating evidence. Would this evidence be admissible? Similarly, could time-traveling officers follow a suspect with no probable cause obtained before the crime if they know from the future that this is a person of interest? Would anything stop these officers from traveling back in time, watching the crime as it happens, and using either their eyewitness testimony or a videotape as evidence? I'm assuming for now that they're not messing with the past by trying to interfere to stop the crime. Thank you for entertaining this silly question.
In part, we don't know because there are currently no rules that address certain outcomes, so it will depend on who is on the Supreme Court when the issue is raised. A warrantless search will not be legal beyond current doctrines regarding crime in progress and imminent danger, even if it involves time travel. So you will need a warrant, and you will need probable cause to get it. Currently, if you break into a person's house to discover that there is a body there, you can't get a warrant to legitimize that illegal search. Adding time travel does not change anything. In situation 1, I assume they have probable cause and a warrant but the evidence was destroyed by the time of the search at time T+n. As long as prior time T is still after the crime, a warrant to search at time T would not be a problem. In scenario 2, there is nothing preventing them from stopping the crime or arresting the perpetrators in the act. However, if they travel back in time and break in to a suspect's house in order to witness the crime, that is an illegal search. You could likewise arrest a person before he escapes to the phantom zone, if you have probable cause that he had committed a crime – by the time of the arrest. Forward time travel poses a more serious challenge, as articulated in Minority Report. It would, or should, be very difficult to issue an arrest warrant at time T based on knowledge of a crime committed at T+n. Because of the arrest, the crime was not committed and there was no probable cause, so there should have been no warrant (oh no, paradox).
Your main misunderstanding is that opposing counsel cannot testify. He can ask a question, such as "Did you say ...?", which provides Einstein an opportunity to answer in a way that maintains the credibility of his testimony, but consel cannot just enter his own testimony into the record. In addition, counsel on "his side" has the opportunity to pose appropriate clarifying questions, e.g. could ask "Did you repudiate that idea 88 years ago?", though there is a problem that the attorney may not have the technical expertise to recognize the subject-matter question that they should ask. Expert testimony does not attempt to determine the state of scholarship in an area, it attempts to resolve a specific factual matter. The two are not the same thing. Einstein would not testify as to what his general and special theories of relativity say, except in a bizarre universe where some person is accused of the crime of denying the theory of relativity. Instead, he might be testifying for the defense, where the defendant is accused of an act that (it turns out) is physically impossible in light of the theory of relativity. If Einstein had been in the habit of posing random mutually-contradictory conjectures on a weekly basis, opposing counsel's question could be relevant to establishing that the witness's testimony is not reliable. Theoretically, counsel could "hint" that the witness is scientifically flighty, so Einstein would have to have a credible explanation for changing his position. It is easy to demonstrate that scientists in general do change their positions as knowledge expands, so Einstein's burden would not be very substantial.
Police can lie However, in the United States they have to read you your Miranda warning (most other democratic countries have similar warnings): You have the right to remain silent. Anything you say can be used against you in court. You have the right to talk to a lawyer for advice before we ask you any questions. You have the right to have a lawyer with you during questioning. If you cannot afford a lawyer, one will be appointed for you before any questioning if you wish. If you decide to answer questions now without a lawyer present, you have the right to stop answering at any time. They have told you everything they are required to tell you - effectively “we are not on your side.” After that, they can lie their asses off. Of course, they wouldn’t ask you for a DNA sample - they’d ask you if you’d like a glass of water. Then they’ll take the DNA from that.
You'd have to specify the cases you want. All court transcripts are a matter of public record, though a copy may cost you a fee from the court clerk's office to recieve. It should be pointed out that not all cases got to an evidentiary stage to actually evaluate on the record any evidence. A vast majority were decided on pre-evidentiary rules such as standing or laches (timeliness) and not all cases that were able induced evidence debunked the evidence. Any appellent case would also not induce evidence as all appeals cases are strictly matter of law rather than matter of fact (evidence), so those cases would be asking a higher court to double check non-evidentiary decisions. The fact that the party that brought the suit does not have standing to bring the suit OR that the party that brought the suit brought it too late for the courts to proceed on the matter does not debunk evidence that the fraud happened in the eyes of the law... it simply means the questions of fact were never addressed at all
The Likely Ruling Assuming points 1 and 2 in the question, all the evidence from the trunk would be inadmissible, and if there really is no other evidence against Bob, then Bob would go free. This is highly improbable; the prosecution would find some grounds to dispute the unlawful nature of stop and search, even if ones the court would not accept. A better version might be &quot;The judge rules that the stop and search were unlawful, and is upheld by the appellate court&quot;. That is more realistic and has the same result. Inevitable Discovery The only grounds I can see for any other result is &quot;inevitable discovery&quot;. If other police were, say, already staking out Bob's house with a warrant to search the car, and Bob was on the way to that house at the time of the stop, then the prosecution could argue that they would inevitably have conducted a legal search of Bob's car and found the same evidence. The conditions for invoking this doctrine rarely occur, but it is possible. After the Trial There is no way that Cal's body can be Bob's property, so it would be released to Cal's next of kin or legal executor. Unless Bob was Cal's next of kin, it is hard to see any way that the body would be handed over to Bob. Cal's clothes are almost surely part of Cal's estate, although it is in theory possible that they are Bob's property. No claim of ownership can be used against Bob in a later trial, because any later trial would be barred by double jeopardy. In any case, while evidence from the trunk would all be inadmissible in a trial of Bob, it might be admissible in a possible later trial of Joe, Bob's alleged accomplice. Therefore the police might well retain all the items (except the body) as possible future evidence. Terminology This is actually about the exclusionary rule itself, not about the &quot;fruit of the poison tree&quot; doctrine. What is the difference? If an unlawful search finds evidence, that evidence is inadmissible under the exclusionary rule. If an unlawful search merely finds a lead, evidence later found via the lead is considered as &quot;fruit of the poisoned tree&quot; and is therefore inadmissible. For example, if the murder weapon is found in Bob's car after an unlawful search, the exclusionary rule applies. But if a note saying &quot;stuf at 1234 Elm&quot; is found during the unlawful search, and the police visit 1234 Elm Street, and find the murder weapon there, that is &quot;fruit of the poisoned tree&quot;. Why does it matter? Because if the police find a different lead to 1234 Elm, so that the investigation or search at that address is not based solely on the results of the unlawful search, then the evidence found at 1234 Elm may be admissible, while corroboration will not save the evidence actually found by the unlawful search. It is a subtle but sometimes important distinction.
The 4th Amendment exclusionary rule applies automatically in cases where law enforcement obtains evidence illegally (subject to exceptions not applicable here). In its 1920 decision in Burdeau vs. McDowell, the U.S. Supreme Court held that the 4th amendment is not applicable to searches by private parties, even when such searches are clearly illegal. This rule doesn't apply, however, if the private citizens was acting as an agent of the government. A more recent case reaffirming and clarifying Burdeau is United States v. Jacobsen 466 U.S. 109 (1984) in which a private courier finds drugs in a package and shows it to police who test the contents (the search was upheld as valid). If the defendant makes that argument, the defendant seeking to exclude the evidence bears the burden of proving by a preponderance of the evidence that the private citizen acted as an agent of the government. U.S. v. Feffer, 831 F.2d 734 (7th Cir. 1987). Another case discussed here notes that: As it relates to computer files, states still differ on how broad the application of the Private Search Doctrine runs, but all seem to agree that if a document or photo has been opened by a private party, an officer can review that file or photo without a warrant. In People v. Wilson, 56 Cal. App. 5th 128 (2020), police opened 4 images they received from NCMEC (the National Center for Missing and Exploited Children) who received the images in a CyberTip from Google. Neither NCMEC nor Google had opened these images in this case, but all 4 images had been reviewed by Google in the past and identified previously as child porn by their matching hash values. So here, the officer’s actions—consisting of opening the electronic files submitted to it by NCMEC and viewing the four images attached to Google’s Cybertip—did not exactly replicate Google’s private actions. The Wilson court set out to determine the degree to which the officer’s additional invasion of Wilson’s privacy exceeded the scope of Google’s private search (the search of his emails against known hash values). Before the officer even received Wilson’s photographs, Google had already reviewed identical images in the past; scanned all of Wilson’s electronic communications to search for content with matching hash values; flagged four of Wilson’s images as matching images Google had previously observed; classified the matching images as depictions of prepubescent minors engaged in sexual acts; forwarded all four images to NCMEC as part of a Cybertip report; and terminated Wilson’s account. The Jacobsen case above explained that, “[t]he Fourth Amendment is implicated only if the authorities use information with respect to which the expectation of privacy has not already been frustrated.” Id. at 117. Because Google’s actions already frustrated any expectation of privacy Wilson possessed in the four photographs at issue, no privacy interest remained in the four images, so no expectation of privacy was violated. Wilson at 219. Because the assigned hash values, or “digital fingerprints,” are representative of the contents depicted in the photographs themselves, the government gained no new material information by viewing the images. The agent merely confirmed Google’s report that Wilson uploaded content constituting apparent child pornography. Id. at 220. When someone who is not law enforcement obtains evidence illegally, the court sometimes engages in a non-constitutional discretionary balancing test to determine if the evidence is admissible. Sometimes it comes in, sometimes it doesn't. I'll find a case setting forth the exact test if I have time. The fact that evidence is &quot;irrefutable&quot; (not that there is any such thing) and widely publicly known is absolutely irrelevant. The fact that a juror knows it would be grounds for excusing the juror for cause and for moving the venue of the trial where they can find enough jurors who aren't familiar with the evidence if they can't manage it in the usual venue.
From a US perspective, in a word, "no". Firstly, "presumption of innocence" is in a trial, not in police interactions. Being arrested does not violate the presumption of innocence. Police do not need any reason to interact with you or ask you questions. Police can arrest you if they have probable cause to suspect you have committed a crime, but this is not always necessary. More on this later(in the fourth section). Secondly, I wouldn't describe requesting to see your ticket, or any document as a "violent communication", in general. It may be rude or insulting, but not violent. (Also "violent communication" is not a legal term. The closest legal terms, verbal assault and threatening communication, are also not this.) More over, there is no indication of am implication of lying in this request. Thirdly, there are many situations in which possessing a document or credential is not sufficient; one must legally display or present them upon request. For example, multiple occupational licenses such as liquor licenses and barber/cosmetology licenses require that the licenses be prominently displayed; whereas, in California at least, a vehicle driver on a public road must not only possess their driver's license and proof of insurance, they must produce them upon the request of any law enforcement officer (Source: https://www.dmv.ca.gov/portal/dmv/detail/pubs/brochures/fast_facts/ffvr18). Fourthly, there are situations in which you can be legally searched and questioned without reasonable suspicion. Examples of this include boarder searches and sobriety checkpoints. Sources: (US Supreme Court rulings): https://en.wikipedia.org/wiki/United_States_v._Martinez-Fuerte; https://en.wikipedia.org/wiki/Michigan_Department_of_State_Police_v._Sitz A note on sources: bdb484 and I have opposing court case sources. My sources have binding precedent over all courts in the US, save the US Supreme Court, whereas theirs don't have any binding precedent, but are more directly on-topic.
We don't have a lot of details, but if you're in the United States, the answer is probably yes. There are rarely any meaningful rules of evidence in student misconduct cases, so pretty much anything can come in. There may be some small difference in the answer depending n whether you're dealing with a public university or private, but in either case, I can't think of any reason why they would not be able to introduce the evidence if they had it. If there's a question about its authenticity, I imagine that would just be up to the misconduct board to decide. If Person X says "Person Y sent this to me," and Person X seems credible, that's probably going to be enough.