The US Army revealed that Johnson served in the army from March 2009 to April 2015 as an army reserve. He carried out one tour of duty in Afghanistan where he was deployed in November 2013 and returned in July 2014.
He was a private first class and from Mesquite, Texas. His military occupational specialty was carpentry and masonry.
Neighbours in Johnson's middle class Dallas suburb told reporters he owned several guns and lived with his mother.
"He was military, I'm not sure if he was still in, so he owned a lot of guns," the female neighbour told The Telegraph. "But he seemed a calm, normal guy. There was never any problem.
"He was protective. He'd ask me if I was OK when I was on my own. When we were out we'd watch each other's houses. He always said Hi.
"I never saw outside with a gun. He did a lot of walking, exercise, around the neighbourhood." Johnson lived with his mother in a two storey detached brick home with a small front garden in a quiet middle class suburb of Dallas. The neighbour said he had lived there since he was a child. A white neighbour said the area used to be predominantly white but black and Mexican families had moved in. But he said: "It's always been peaceful here."
Authorities carried several bags of unknown materials from Johnson's home in the Dallas suburb of Mesquite on Friday.
What happened?
Five police officers were killed and another seven injured when snipers opened fire on them from rooftops in Dallas at a protest on Thursday evening.
Police initially thought multiple shooters had levelled fire on them, but by Friday morning were less clear whether there was more than one attacker.
One sniper, thought to be Micah Johnson, has been killed while exchanging gunfire with authorities at a parking garage in Dallas, while two other suspects are in custody. Police officers surrounded a car park near El Centro College where an armed man was firing off rounds with a rifle.
On Thursday, five police officers were killed and seven were injured after a sniper attacked a public protest march in downtown Dallas, Texas. Sources indicate at least three other people were taken into custody for questioning relating to the attack. The march was held to protest the shooting deaths of Alton Sterling in Louisiana and Philando Castile in Minnesota during engagements with police officers.

Police identified 25-year-old Micah Johnson as the suspect. Johnson had previously served in the US army, and police reported he said he wanted to exact revenge upon police officers after news of Sterling and Castile's deaths. Ammunition and weapons were found inside Johnson's home. Dallas Police reported the policemen were shot at from a height. Officials said two civilians were also injured in the attack. 
File photo of police car lights.
Micah Johnson served for the  from 2009 until early 2015, including a tour of Afghanistan. Johnson had no criminal record.  His attack was reported to be a lone mission.

After the attack earlier on Thursday, police killed Micah Johnson in 's parking lot by a bomb explosion.

Hillary Clinton, 2016 United States presidential election candidate and favorite for the Democratic nomination this July, said, "There is too much violence, too much hate, too much senseless killing, too many people dead who shouldn't be. No-one has all the answers. We have to find them together." 

After Johnson was killed, , Dallas' mayor, said "We believe now the city is safe".