The only thing I have ever heard them on is the 155.4000 frequency we have listed in the DB.
You may want to search through business licenses (IG) to see if they have something there.
As stated above, they do use 155.400 with PL of 110.9 for 99.9% of their security comms. I'm still trying to confim that Southview and Grandview security are both using 461.475 (seperate low profile repeaters).