When is a search warrant considered invalid?

A search warrant is considered invalid if it is not signed by a judge. The judicial signature is a crucial component of a search warrant as it signifies that a judge has reviewed the application and determined that there is probable cause to believe that evidence of a crime will be found in the location specified. This requirement is essential to uphold constitutional protections against unreasonable searches and seizures, ensuring that law enforcement actions are backed by judicial oversight rather than arbitrary authority.

Other factors, such as the time of execution or the presence of a suspect, do not inherently invalidate a warrant; rather, these may affect the manner in which the warrant is executed but do not undermine the legal legitimacy of the warrant itself. Thus, the absence of a judicial signature directly compromises the warrant's validity.