Grief, politics and a day of presidential contrasts

President Obama reacts to Dallas shootings from Warsaw

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What black men in Dallas need you to know

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Obama speaks at Dallas service for slain officers

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Dallas police chief recites Stevie Wonder at service

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Dallas mayor: Officers died trying to stop the violence

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Barack Obama July 12 Dallas police memorial

President Obama: We all know racial bias exists

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Dallas trauma surgeon Brian Williams talks to Don Lemon about the Dallas shootings

Dallas trauma surgeon: This has to stop

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Surgeon describes treating Dallas officer (Part 1)

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Surgeon describes treating Dallas officer (Part 2)

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Dallas survivor: Officer yelled, 'He's got a gun!'

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CNN's Sara Sidner shows you what a pound of C-4 on a robot arm does in light of the Dallas Police tactic against a sniper.

How Dallas police used a robot bomb to stop shooter

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Opposing protesters meet in Dallas

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Dallas shooter's parents speak out for first time

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Police: Dallas shooter was singing during standoff

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Shooting survivor, family talk about attack

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Police: We'll give our lives for your right to protest

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DALLAS, TX - July 8, 2016: Dallas Mayor Mike Rawlings (R) looks on during a press conference at Dallas City Hall as Dallas Police Chief David Brown speaks on the fatal shootings of five police officers on July 8, 2016 in Dallas, Texas. At least one sniper killed five officers and wounded seven others in a coordinated ambush at a anti-police brutality demonstration in Dallas. The sniper was killed, and three other people are in custody, officials said. (Photo by Stewart F. House/Getty Images)

Dallas police chief praises officers during shootings

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Protesters and police clash in Arizona

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What cops and African-Americans have in common

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Dallas protest shattered by ambush shooting

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Dallas Mayor Mike Rawlings says they believe Dallas police shooter Micah Xavier Johnson acted alone

Dallas mayor confirms gunman was the lone shooter

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Bystanders stand near pollice baracades following the shootings.

Shooting at Dallas protest in 60 seconds

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Dallas Police respond after shots were fired at a Black Lives Matter rally in downtown Dallas on Thursday, July 7, 2016. Dallas protestors rallied in the aftermath of the killing of Alton Sterling by police officers in Baton Rouge, La. and Philando Castile, who was killed by police less than 48 hours later in Minnesota. (Smiley N. Pool/The Dallas Morning News) -- MANDATORY CREDIT, NO SALES, MAGS OUT, TV OUT, INTERNET USE BY AP MEMBERS ONLY

Chaos in Dallas as 12 officers are shot

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TOPSHOT - Bystanders stand near pollice baracades following the sniper shooting in Dallas on July 7, 2016.
A fourth police officer was killed and two suspected snipers were in custody after a protest late Thursday against police brutality in Dallas, authorities said. One suspect had turned himself in and another who was in a shootout with SWAT officers was also in custody, the Dallas Police Department tweeted.
/ AFP / Laura Buckman (Photo credit should read LAURA BUCKMAN/AFP/Getty Images)

Police: Suspect said he wanted to kill white officers

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A Dallas police officer, who did not want to be identified, takes a moment as she guards an intersection in the early morning after a shooting in downtown Dallas, Friday, July 8, 2016. At least two snipers opened fire on police officers during protests in Dallas on Thursday night; some of the officers were killed, police said.

Desperate calls from Dallas officers during ambush

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Video from balcony shows Dallas shooting

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People rally in Dallas, Texas, on Thursday, July 7, 2016 to protest the deaths of Alton Sterling and Philando Castile.
Black motorist Philando Castile, 32, a school cafeteria worker, was shot at close range by a Minnesota cop and seen bleeding to death in a graphic video shot by his girlfriend that went viral Thursday, the second fatal police shooting to rock America in as many days. / AFP / Laura Buckman (Photo credit should read LAURA BUCKMAN/AFP/Getty Images)

'It looked like an execution'

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See video of Dallas shooting

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Police: Suspect said he's going to kill more

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Gunshots ring out in Dallas, officers killed

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Dallas witness: People were trampled following gunshots

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Witness describes Dallas police officer getting shot

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Dallas shooting witness: I heard about 20 gunshots