If you are a sworn, active LE officer, I'd check a few of the forums or message boards like www.Silencertalk.com
for details about cans/sound reduction add-ons.
If you are in south Florida, you may want to contact Knight's Armament company in Vero Beach FL. They do a lot of DoD/spec ops work.
Other big names include Surefire, Gem-Tech & AWC.
I'm not a sworn LE agent or officer, but I'm curious to know if your LE agency or supervisor allows you to buy/use surpressed weapons on duty.
Is the agency not buying or obtaining any weapon contracts or do they allow PODA(private owned, dept approved) weapons/gear/ammunition?
Stay safe & catch lots of bad guys!