In United States v. Tobin, the magistrate and district court found that the police had reasonable suspicion of criminal activity when they approached the defendant's house. The key issue was whether the police officer's conduct at the door of the house, which afforded him the opportunity to smell the marijuana, precipitated an impermissible search to which the defendant did not consent. A police officer's approach to a criminal suspect's house to make general inquiries is not a search as long as the door is not opened in response to a threat or command. Because in its view the agent's conduct at the door amounted to a demand of entry under color of authority, however, it was found that the opening of the door constituted a search to which the defendant could not have consented. The olfactory access to the house which the agent gained pursuant to the opening of the door was therefore illegal, and the searches which followed were consequently tainted. However, it was found later that the defendant did not have standing to assert the fourth amendment violation. Consequently, the evidence uncovered in the search was admissible against him.