Officer Johnson received an e$-$mail message from a total stranger named Art. The e$-$mail detailed how Bob, a convicted felon, was running a retail cocaine business out of his apartment. Bob would drive each week to Long Beach Harbor and pick up a shipment of coke and return home to apartment C in the Avalon apartment complex located on $1848$ Plum Street in Anaheim. The e$-$mail further indicated that Bob would store the product in his kitchen cabinets and transact business out of his apartment. Customers would arrive at all hours of the night, enter his apartment and leave with brown paper bags containing cocaine. Officer Johnson surveilled Bob$$s house for a week. On one evening he even followed Bob to Long Beach Harbor and observed Bob pick up a crate and return to the apartment complex with the crate. Bob then put the crate on a dolly and wheeled it into the elevator of the three$-$story complex. Officer Johnson observed individuals entering the elevator after midnight and into the early morning hours. The same individuals would leave the complex carrying small brown paper bags within $10$ minutes of their arrival. So Officer Johnson included all of this information in an affidavit and applied for a warrant. The magistrate carefully read through the affidavit and warrant and approved the warrant. The warrant was then executed by Officer Kennedy and a team of officers. However, when they arrived at the apartment complex, they realized that there was an apartment C on each floor of the complex. Officer Kennedy immediately made the observation that apartment C couldn$$t be on the first floor because the facts in the affidavit described Bob taking an elevator. That left the second and third floors as the only options. Officer Kennedy then looked at the mailboxes located in the hall of the apartment complex. The name of the occupant on the second floor was Susan Wilson. The name of the occupant listed on the third floor was Bob Carter. So$,$ officer Kennedy and his team took the elevator to the third floor and knocked and announced their presence. Bob answered the door and was handed a copy of the warrant and affidavit. Bob was detained at the front door by Officer Kennedy. The other officers searched the kitchen cabinets where they found the cocaine. One of the officers also seized a handgun in the kitchen cabinet. It is illegal for convicted felons to possess firearms. Bob was immediately arrested and searched. A baggie of cocaine was found in his wallet.

Discuss all legal issues relating to $(1)$ the validity of the search warrant; $(2)$ the detention of Bob in the doorway of his apartment; $(3)$ the seizure of the handgun; and $(4)$ the seizure of the cocaine from Bob$$s wallet.