Anonymous 02/09/2018 (Fri) 23:32:20 No.12380 del
Software support. Most UNIX-like systems lack support for mainstream tools that these guys need. Also, the US government has contracts with Microsoft, as well as universities.
The server running the services from police is most likely a gnu/linux or BSD system.

Some sensitive groups in inteligence agencies don't use Windows because of security, just the 'normal' police.