Passivity in Statement Analysis
Passivity is used to conceal identification and/or responsibility.
When passivity is used, there is a psychological 'softening' affect upon the reader/listener. When identity or responsibility is obfuscated, the words directly before or after can lead the reader/listener to an opinion.
"Stones fly; police fire teargas..."
Here, we know that stones do not "fly", they must be thrown or projected by someone. To use passivity, the propaganda technique is concealing the identity of who threw the stones. Yet, German government, no stranger to propaganda, knew to place the term close to the police action. This will have a slight affect for some readers to not only not think of who is hurling stones, but may even tie this activity with "police."
This, along with clever editing (see Making a Murderer) equals deceptive propaganda.