Two Iraq war veterans are among the five police officers killed by sniper fire Thursday night after an anti-police violence rally in Dallas, Texas turned violent.
The suspect, 25-year-old Micah Johnson, died after a long stand-off with police in central Dallas.
With the lone shooter dead, Mayor Mike Rawlings declared that the city was safe and "we can move on to healing".
Protesters hold placards against the killing of Alton Sterling and Philando Castile in Manhattan, New York, U.S on July 7, 2016.
Army Lieutenant Colonel Major Michael Waltz, a former special forces officer and White House aide, said in an interview with Reuters that a video of the attack indicated that Johnson was "not only trained, but well trained".
Johnson told Dallas police in the parking garage where he was cornered that he was upset about the recent fatal police shootings of black men.
This week's killings of two black men by police officers in Louisiana and Minnesota were the latest in a long string of similar, controversial killings that have led to nearly two years of national protests over race and justice.
The protesters are now in a stand-off with police as they block a major road.
Police in Dallas said the bomb-making material was found when they searched Micah Johnson's home in the suburb of Mesquite.
Rawlings also says the suspect used an AR-15 rifle.
The man named as the key suspect in the deadly Dallas shooting rampage was an army reservist who had served in Afghanistan, the USA military said on Friday.
Giles said he never heard his cousin talk about wanting to carry out an attack or wanting to harm someone.
"The suspect stated he was not affiliated with any groups and he stated that he did this alone".
The city's top cop took to twitter on Friday to express his condolences to those affected by the tragic event in Dallas stating: "What happened in Dallas last night and this morning is shocking".
Police have not disclosed a motive in Friday's attacks in Georgia and Missouri, which have been described as ambushes. That sparked a shootout in which both the officer and suspect were wounded but expected to survive.
Details continue to emerge about the shooting, which left five officers dead, seven others wounded and also injured two civilians.
President Barack Obama said America is "horrified" by the shootings, which have no possible justification.
He later ordered all flags on public buildings to be flown at half-mast. "And to be viciously taken down, and their life taken from them, is devastating", Bilal says. No-one has all the answers. "We have to find them together".
"You know some of the things that occur like in Dallas, you can't really prepare for something like that", Sheriff Crish said. Thank you to our community who makes us feel appreciated.