Police were concerned about an increase in marijuana traffic in Defendant's neighborhood. One night, Police Officers, accompanied by dogs trained to sniff out marijuana, went into the backyard of Defendant's house and onto his porch. Defendant and his friend were inside 34 having dinner. The dogs acted as if they smelled marijuana. Police Officers knocked on the back door. Defendant answered the door and let them in. Defendant was immediately placed under arrest. After a brief search, Police Officers confiscated a large quantity of marijuana which they found in Defendant's linen closet. Defendant's motion to prevent introduction of the marijuana into evidence will most probably be
denied, because the search was incident to a valid arrest.  denied, because Defendant permitted Police Officers to enter his house.  granted, because under the circumstances the police activity violated Defendant's reasonable expectations of privacy.  granted, because this kind of detection by trained dogs has not been scientifically verified and cannot be the basis for probable cause.