Warning: Video contains content that may disturb.
A video showing the Dallas gunman shooting down a police officer makes it clear he had undergone extensive tactical training, according to military experts.
Dallas police have identified Micah Xavier Johnson, 25, a former member of the US Army Reserve, as the shooter.
In the footage, recorded by Randy Biart, the gunman wears tan coloured clothing, and is seen crouching behind a rubbish bin next to the pillar of an office building.
In a confrontation with a police officer, he can be seen bobbing and weaving - while firing - and circling the building pillar before firing more rounds into the collapsing body of the officer.
The video is believed to show the fifth police officer killed in the attack, which also wounded a further seven police officers and two civilians.
Johnson was a private first class in the US Army Reserve from March 2009 to April 2015. He was deployed to Afghanistan from November 2013 to July 2014 and earned a number of service medals, according to US Army records.
Michael Waltz, a former US Army Special Forces officer and White House aide who served in Afghanistan, said the shooter depicted had "certainly" undergone training.
"He is using his rifle in the way that we are trained," Mr Waltz said. "He runs directly into fire with the police officer and then flanks him."
Other indications of training, Mr Waltz said, are the way the shooter raises and lowers the rifle to his shoulder, and appears to squeeze off two rounds at a time.
At one point, the apparently right-handed gunman weaves to the left - firing to the left of the pillar - before circling it to the right and closing on the victim with a barrage of close-range shots.
Any such attack would have required extensive plotting, said Terry Turchie, former deputy assistant director of the FBI counter-terrorism division.
"He was obviously on a mission and had all the training he needed," Mr Turchie said after watching the video of the shooter.
"You can't carry out something like that without planning ahead of time."
Dallas Mayor Mike Rawlings described Johnson this way late Friday: "This was a mobile shooter that had written manifestoes on how to shoot and move, shoot and move.
"And he did that. He did his damage, but we did damage to him as well."
While authorities, including the mayor of Dallas, said they believe Johnson was the lone gunman, they are still looking into whether there were co-conspirators.
Newshub. / Reuters