Philando Castile

The suspect in the deadly attack on Dallas police officers scrawled letters in his own blood on the walls of the parking garage where officers cornered and later killed him, the police chief said Sunday.

Police agencies across the U.S. are on edge and on guard after receiving threats and calls for violence against them on social media in the aftermath of the killings of two black men and the sniper attack that left five officers dead in Dallas. Some departments ordered officers to pair up or more generally said they were heightening security.

Can this really be America in 2016?

The black Army veteran who killed five Dallas police officers donned a protective vest and used a military-style semi-automatic rifle in the sniper slayings, officials said, an attack that layered new anxiety onto a nation already divided about guns and how police treat African-Americans.

When Philando Castile saw the flashing lights in his rearview mirror, it wasn’t unusual. He had been pulled over at least 52 times in recent years in and around the Twin Cities and given citations for minor offenses including speeding, driving without a muffler and not wearing a seat belt.