(I’ll be honest: this post isn’t really about the fruit of the poisonous tree so much as it’s about Sherlock’s possible status as a state actor and thus whether or not the restrictions of the Fourth Amendment apply to him. The poisonous tree bit just makes for a snappier title and is at least somewhat related to the main topic.)
In many ways Sherlock Holmes is the Ur-superhero, prefiguring Batman. They are both detectives possessing no supernatural abilities, only a keen intellect, physical training, a faithful assistant, and a relentless drive to solve or prevent crime. In the case of the Sherlock Holmes of Elementary, they even share a certain degree of wealth — though Sherlock doesn’t flaunt it, he does use his wealth to solve problems on a few occasions. They also share a strong connection with the police.
It is that connection with the police that is so often a troubling feature of Elementary. Often Sherlock will make a point of his police affiliation in order to gain access to a building or get a person of interest to talk. But at other times he will claim that, since he is not a police officer, he does not need a warrant to perform a search (searches that often include breaking and entering). Which is closer to the truth? Or can he have it both ways?
I. The Fourth Amendment and the State Action Requirement
Like most of the Constitution, the Fourth Amendment restricts the powers of the federal and state governments, not private individuals. In every state except Texas, if a non-state actor independently performs an illegal search or seizure, any evidence obtained is still admissible. In every state, if a government agent does so, any evidence obtained — and any evidence derived from that [...]