Police Union of German States
... that the secret police of several German-speaking nations exchanged intelligence with each other through the Police Union of German States from 1848 to 1866?
... that the <a href="./Secret_police" id="mwCPc" rel="mw:WikiLink" title="Secret police">secret police</a> of several German-speaking nations exchanged intelligence with each other through the <b id="mwCPg"><a href="./Police_Union_of_German_States" id="mwCPk" rel="mw:WikiLink" title="Police Union of German States">Police Union of German States</a></b> from 1848 to 1866?