This is easy to get around, often the copyright will just be held by a contractor.
Unlike works of the U.S. government, works produced by contractors under government contracts are protected under U.S. copyright law . The holdership of the copyright depends on the terms of the contract and the type of work undertaken.
Wait, the LAPD is a government entity. They are funded with public taxpayer money.
They cannot own a copyright or a trademark. It belongs to the public.
EDIT: this is also why you can use NASA footage and audio recordings royalty free in your own works. Because you already paid for them.
You can use any US Military footage from dvidshub.net as well.
This is easy to get around, often the copyright will just be held by a contractor.