>Why can they lie to us, but we can't lie to them?
Same reason they can arrest you and you can't arrest them.
One of the jobs of the police is to investigate crimes. Deceit, when used properly, is one tool in the toolbox for good and effective police/detective work. I mean the typical "good cop, bad cop" interrogation technique can be considered deceitful.
They must use deceit (and other tactics) within the confines of due process of law to protect the accused as well as the public at large. Courts use the term "shocks the conscience" for the type of deceit that, well, shocks the conscience, and that type of deceit isn't allowed. There isn't an exact line drawn in the sand over when legitimate police work turns into "shocks the conscience" behavior because it can be somewhat subjective at times. However, a clear example would be a police officer pretending to be the suspect's court appointed attorney in order to gain evidence. See also: Rochin v. California[1]
If police posed as paramedics in order to enter your house, that definitely would pass the "shock the conscience test" thus violate due process of law. Doubly so if they somehow purposely injured you or your spouse to get you to call.
Furthermore, police don't need to obtain a search warrant if they have probable cause. The plain view doctrine[2] would likely apply as long as the officer was lawfully in your home (you invited her in for tea) and all your murder weapons covered in blood were laid out on the coffee table. I'm being hyperbolic, but you get the point. The officer also doesn't need a warrant if you consent to a search. Your consent can be taken away at any time though.
And here[3] are two recent cases out of New York (these are state court, not federal, but I still think they are good examples of the concept)
>In a unanimous ruling, the New York State Court of Appeals tossed out the 2009 conviction of Adrian Thomas for the murder of his infant son, finding that Troy, N.Y., police had overstepped their prerogative to use artifice when they told Mr. Thomas that his son, who was brain-dead, was alive and could be saved with his confession, among numerous other falsehoods.
>In another decision on Thursday, the court also upheld a lower court’s ruling to overturn the conviction of Paul Aveni for criminally negligent homicide in his girlfriend’s heroin overdose death. The court agreed with the earlier ruling that police had coerced Mr. Aveni into confessing, telling him that his girlfriend was still alive, but could die if he did not tell them what drugs he had given her, so that she could receive proper treatment.
It is all a delicate balancing act to try to keep the system fair to everyone.
And FYI, I am under no illusion that there are no corrupt police, things always are perfect, etc., etc. I just am trying to give an overview of the concepts, the implementation is not perfect.
Same reason they can arrest you and you can't arrest them.
One of the jobs of the police is to investigate crimes. Deceit, when used properly, is one tool in the toolbox for good and effective police/detective work. I mean the typical "good cop, bad cop" interrogation technique can be considered deceitful.
They must use deceit (and other tactics) within the confines of due process of law to protect the accused as well as the public at large. Courts use the term "shocks the conscience" for the type of deceit that, well, shocks the conscience, and that type of deceit isn't allowed. There isn't an exact line drawn in the sand over when legitimate police work turns into "shocks the conscience" behavior because it can be somewhat subjective at times. However, a clear example would be a police officer pretending to be the suspect's court appointed attorney in order to gain evidence. See also: Rochin v. California[1]
If police posed as paramedics in order to enter your house, that definitely would pass the "shock the conscience test" thus violate due process of law. Doubly so if they somehow purposely injured you or your spouse to get you to call.
Furthermore, police don't need to obtain a search warrant if they have probable cause. The plain view doctrine[2] would likely apply as long as the officer was lawfully in your home (you invited her in for tea) and all your murder weapons covered in blood were laid out on the coffee table. I'm being hyperbolic, but you get the point. The officer also doesn't need a warrant if you consent to a search. Your consent can be taken away at any time though.
This is a really really great overview on the topic - http://policelink.monster.com/training/articles/1911-lying-t...
And here[3] are two recent cases out of New York (these are state court, not federal, but I still think they are good examples of the concept)
>In a unanimous ruling, the New York State Court of Appeals tossed out the 2009 conviction of Adrian Thomas for the murder of his infant son, finding that Troy, N.Y., police had overstepped their prerogative to use artifice when they told Mr. Thomas that his son, who was brain-dead, was alive and could be saved with his confession, among numerous other falsehoods.
>In another decision on Thursday, the court also upheld a lower court’s ruling to overturn the conviction of Paul Aveni for criminally negligent homicide in his girlfriend’s heroin overdose death. The court agreed with the earlier ruling that police had coerced Mr. Aveni into confessing, telling him that his girlfriend was still alive, but could die if he did not tell them what drugs he had given her, so that she could receive proper treatment.
It is all a delicate balancing act to try to keep the system fair to everyone.
And FYI, I am under no illusion that there are no corrupt police, things always are perfect, etc., etc. I just am trying to give an overview of the concepts, the implementation is not perfect.
[1]http://en.wikipedia.org/wiki/Rochin_v._California
[2]http://en.wikipedia.org/wiki/Plain_view_doctrine
[3]http://www.csmonitor.com/USA/2014/0221/How-much-can-police-l...