The Courts release the evidence back to SPD so that they can properly be released to its rightful owner. I don't understand how the DOJ can step in and obtain that property without either a search warrant or permission from the owner. This is so far off-base in determining the racial animus they need to bring Federal charges against Zimmerman in my mind. Why didn't they just go for all of the FBI reports? I suspect that MOM was correct when he said that collection was much bigger than the 40 pgs released.
"How" is easy. Possession trumps the law.
Going after errant government action is a financial decision. Zimmerman is armed, he has no need of his property, so it's cheaper to allow the government to cheat than it is to challenge the illegal action. I figure if Zimmerman did sue, it would be trivially easy for the DOJ to get a warrant.