The underlying article actually indicates that someone shot the window out of a bus accompanying the marchers.

Somebody shot the window out of the back of one of the buses traveling with the march, dubbed by the NAACP as the Journey for Justice. The outer pane of glass broke. The bullet landed in the windowsill, the driver said.

The people opposed to the march weren’t just protesting with words or with flags.

They make their intentions and hostilities known with violence.