He went in and gave a statement to the police. Why did they not take him into custody then? Why the wait? If the charge was that serious, they should have arrested him when he gave his statement. If he were arrested at the police station, then the police would not have been able to get into his house to serve the warrant. If he is arrested in the house, police can break into the house to serve the warrant, and can discover any incriminating evidence (guns, lots and lots of guns) in the process of serving the arrest warrant.
If he were arrested anywhere else, they would have to obtain a separate search warrant to search the house. If the case against him (just speculating now) is weak, they would probably not be able to get a search warrant, leaving all of those pretty guns unsiezed.
Now, I'm trying to remember, it's shiny side out, right?
"If he were arrested at the police station, then the police would not have been able to get into his house to serve the warrant. If he is arrested in the house, police can break into the house to serve the warrant, and can discover any incriminating evidence (guns, lots and lots of guns) in the process of serving the arrest warrant."
IF they had probable cause to believe that there was illegal items in the house (aside from the desire for a lazy fishing expedition), they should have gone to a judge and gotten a SEARCH WARRANT.
Meanwhile, they brilliantly achieved their objective by BURNING THE HOUSE DOWN.