Hey guys, so I just got done watching a crash course video on civil liberties, and according to a (I guess you could say civil case) it states that states cannot gather evidence from a warrant less search, now my question is why is that? What if the investigator or agent finds the murder weapon and has solid proof that it is, why must they always have a warrant even if the weapon was the one used in the crime? (Eg. robbery, home invasion, etc). 

 

Edited July 18, 201510 yr by TheSandwichStealer

I haven't heard of that before, a link to the video would be nice.. because something doesn't seem right. Then again most murder cases the murder weapon is left at the crime scene, or tossed somewhere close (since it's in public Criminalists or Officers can take it and bag it). however if the killer took the weapon with him then you'll obtain a search warrant later on in the investigation (that's if you have enough evidence to obtain one).

But in general, to collect evidence and it's not in public (ie. At a suspects house) you'll need a search warrant otherwise whatever you find is invalid. That being said each case is different so the laws/rules between obtaining evidence from a robbery might be different to obtaining evidence of a murder. 

Here is the video:

 

https://m.youtube.com/watch?v=kbwsF-A2sTg

The correct name is Mapp v. Ohio; "vs." is not used in court case names, as the standard abbreviation is "v."

Mapp was a criminal case, not a civil one, and it extended something to the states that already existed for the federal government. Basically, an unconstitutional search is illegal. Without any sort of consequence for that illegal search, there's no reason for police not to do it. There are various ways you can try to disincentivize it, but if you let the evidence be heard in court it's pretty much equivalent to letting a bank robber keep the money they stole -- they might face consequences, but they got what they wanted in the first place. At the federal level the rule already existed, but at the state level the Court had decided that states could adopt other ways to discourage illegal searches (in Wolf v. Colorado). Mapp was the Court saying "nothing else is enough, so we're going to say this is the only acceptable way to discourage illegal searches."

From what I've heard, it is hard in practice to get evidence excluded; judges don't like to do it, and there are plenty of exceptions. But the basic point of the rule is as a deterrent to cops who would otherwise have no reason to obey the Constitution.