Micah Johnson Dallas gunman left cryptic messages in his own blood

But, as the nation continues to be roiled by protests against police-involved shootings, Brown made an emotional plea for a “silent majority” of the public to express appreciation for officers.

The suspect who killed five police officers in Dallas last week had prepared a larger assault on law enforcement, the city’s police chief said on Sunday, citing evidence gathered from the killer’s home that showed he had practiced with explosives.

Taunts During exchanges with police negotiators, Johnson taunted officers, asking how many policemen he had killed, played games, laughed at police, threatened to kill more police and even sang, Mr Brown said. The black Army veteran was killed by a robot-delivered bomb after the Thursday evening shootings. So that’s five officers killed, nine officers injured and two civilians hurt in the attack.

“As a policing family here in Dallas and across the country, there is a heightened sense of awareness around threats we received all over the country”, he said.

“I think about it every day that I was unable to save those cops when they came here that night”, he said. “I’d do it again”.

Johnson’s military training helped him to shoot and move rapidly, “triangulating” his fire with multiple rounds so that police at first feared they were facing several shooters.

Police in the USA city of Dallas, Texas, stepped up security Saturday after a new threat was received, two days after snipers killed five police officers during a mass protest in the city.

Although police believe Johnson acted alone, “we still have not ruled out whether or not others were complicit”, Brown said.

“If lethally equipped robots can be used in this situation, when else can they be used?” says Elizabeth Joh, a University of California at Davis law professor who has followed US law enforcement’s use of technology. His six years in the Army Reserve, including a tour in Afghanistan, were “not what Micah thought it would be. what he thought the military represented, it just didn’t live up to his expectations”.

“Me and my family have received death threats nearly immediately after the shooting”, Brown said.

Dallas Mayor Mike Rawlings said those protesters led to some confusion during the shootings.

The astonished father added: “I don’t know what to say to anybody to make anything better”.

Brown said Johnson was in a position where officers would have had to expose themselves to “grave danger” to get a shot at him.