Then at a protest over those killings in Dallas, five police officers were shot dead.
"We wake up everyday now with a new public tragedy," activist Allison Padilla said.
Padilla says people everywhere are fed up.
"I think that there are people frustrated and I think that they should be frustrated," Padilla said.
The frustration and tension is also felt by law enforcement says security expert and reserve police officer Hector Alvarez.
He has friends in the Dallas Police Department.
"I didn't know a single person who lost their ives last night but I feel like I lost a brother or like I lost a sister," Alvarez said.
Alvarez says it's troubling knowing even police officers are vulnerable to gun violence.
"I think when society as a group swings so far that the people we have who are sent to protect us are then unable to protect themselves, it's a pretty scary feeling," said Alvarez.
Former Sacramento County Sheriff John McGinness says this mass shooting of officers may prompt police departments to reexamine their tactics.
"I guarantee you Dallas police department and other law enforcement agencies across the nation will look at what was done in Dallas and what could be done better," McGinness said
In the wake of so much loss, Padilla and Alvarez agree on this:
"It creates a greater reason for us to stand up and act," Padilla said.
"We can no longer sit on the sideline and not participate," said Alvarez.
They believe people need to step up in order to break the cycle of violence and death.
"I'm 100 percent optimistic that it'll get better because I strongly believe there are more good people than bad," said Alvarez.
A protest at the State Capitol Friday prompted guards to close the building at 4:30 p.m.