He lived with his parents. The FBI searched the home on January 8 with a warrant. You can see that info in the Criminal Complaint here:
http://media.washingtonpost.com/wp-srv/politics/documents/Loughner.pdf
I don’t know why the family would not allow them back in. There must be more to the story.
Could it be possible that both parents have conspired to commit ‘suicide by cop’ - and thus the baricade?
How long is a warrant good for? Can they come back days latter with it or do they need a new one?