Police trying to control the Ferguson protests and riots responded with an uncoordinated effort that sometimes violated free-speech rights, antagonized crowds with military-style tactics and shielded officers from accountability, the Justice Department says in a document obtained Monday by the St. Louis Post-Dispatch.

“Vague and arbitrary” orders to keep protesters moving “violated citizens’ right to assembly and free speech, as determined by a U.S. federal court injunction,” according to a summary of a longer report scheduled for delivery this week to police brass in Ferguson, St. Louis County, St. Louis and Missouri Highway Patrol.

The report suggests that last year’s unrest was aggravated by long-standing community animosity toward Ferguson police, and by a failure of commanders to provide more details to the public after an officer killed Michael Brown.