The man who shot dead five police officers during a protest in Dallas had been planning a killing spree on a much larger scale, it has emerged.

Micah Johnson, a 25-year-old army reservist, shot 12 police officers and two civilians during the Black Lives Matter protest last week before being killed by a police bomb squad robot.

Dallas police chief David Brown told CNN that investigators have examined the bomb-making materials and combat journal found at Johnson's home.

Image: Micah Johnson was a follower of several black militant groups on Facebook

He added that they believed Johnson had been "practicing explosive detonations and that the materials were such that it was large enough to have devastating effects throughout our city and our north Texas area".

Johnson had also practiced military-style drills on his property and trained at a private self-defence school that teaches special tactics, including "shooting on the move", where an attacker fires and changes position before firing again.


Image: Police officers stand guard outside Micah Johnson's home

Mr Brown said: "We're convinced that this suspect had other plans" but that the deaths of two black men in Minnesota and Louisiana had "sparked his delusion to fast-track his plans and (he) saw the protest in Dallas as an opportunity to begin wreaking havoc on our officers."

:: Dallas Shooter Followed Black Militant Groups On Facebook

The police chief told how Johnson had taunted officers during the standoff before his death.

He said: "We had negotiated with him for about two hours and he just basically lied to us, playing games, laughing at us, singing, asking how many did he get and that he wanted to kill some more."

Meanwhile, a sheriff in Louisiana has said that seven weapons have been confiscated from the more than 130 people protesting the killing of two black men by white officers.

Most of the arrests were for trying to block highways and police said that the only reported injury was to one officer.

Governor John Bel Edwards said he was "very proud" of the police response to the protest, adding that he didn't believe they had been overly aggressive in using riot gear to move protesters from the road.