Sniper Who Killed 5 Dallas Police Officers Acted Alone, Authorities Say

Dallas Police Chief David Brown pauses at a prayer vigil <br>

Flowers and notes cover a Dallas police cruiser<br>

Flags are at half mast outside Dallas City Hall <br>


At a prayer vigil<br>

Micah Johnson's residence in Mesquite, a suburb of Dallas<br>

Homeland Secretary Jeh Johnson, with NYC Mayor Bill de Blasio and NYPD Commissioner Bill Bratton, discussing the shootings<br>

A man with "Police Lives Matter" shirts in Dallas<br>

A person writes a note to put on a Dallas PD cruiser<br>

Girls bring flowers to a Dallas PD cruiser outside police headquarters<br>

At the prayer vigil in Dallas<br>