Different types of police tactics during investigations have different classifications. Some are classified as searches.
When does a police investigative action constitute a search? Generally, a search occurs when police conduct invades on something that an individual has a legitimate expectation of privacy in.
Why does it matter whether a particular tactic police use constitutes a search? It does because police searches have a wide range of rules connected to them. Evidence found as a result of searches that run afoul of applicable rules may be found inadmissible. Thus, whether a given tactic was a search can impact what conditions have to be met for evidence deriving from the tactic to be admissible.
Given this, whether a given thing a police tactic targeted is something a person has a legitimate expectation of privacy in can be a very impactful issue in criminal cases, like drug or sex offense cases. Now, over the years, a lot of standards have been set regarding what things a person generally does and does not have a legitimate expectation of privacy in. Thus, sometimes, whether a given police tactic was a search is a pretty straightforward issue. However, there are still some murky regions in this area of law.
This underscores the complexity of the issues that can arise in criminal cases when it comes to evidence uncovered by police investigative tactics. It also shows why having a criminal defense attorney who is very knowledgeable on the laws and rules regarding police searches and other police tactics can be very important when facing allegations of criminal activity.
Source: FindLaw, "Illegal Search and Seizure FAQs," Accessed Feb. 8, 2016