I can’t vouch for it, but the article I read yesterday stated that the police department violated a federal law governing how law enforcement seizes information from journalists. If so, the feds could become involved.
Basically go up the food chain. This corruption is probably more on the magistrate who signed the warrant than the police who served it, but that gets investigated by the state or the DOJ.
The FBI, but they're too busy grooming mentally disabled people into fabricated terror plots, because real terrorism is far too rare to justify their inflated headcounts and budgets.
https://www.fbi.gov/about/faqs/does-the-fbi-investigate-graf...
https://en.wikipedia.org/wiki/Hobbs_Act
Really goes to show you how wide interstate commerce clause goes.