Micah Johnson, the man who has been accused of killing five police officers and injuring 7 others in a gun attack at a protest rally in Dallas, is said to have acted alone according to officials.

However, investigators are looking into links with black power extremist after they found that the gunman was following several militant groups, all of whom advocate violence against police on social media.

Police Chief David Brown commented on the event, stating at a news conference:

“He said he was upset about Black Lives Matter; he said he was upset about the recent police shootings. The suspect said he was upset at white people. The suspect stated that he wanted to kill white people, especially white officers.”

The 25-year-old Johnson was a private who previously did a nine-month tour of Afghanistan after being part of the Army Reserve for 6 years. However, six months into the 9-month tour of Afghanistan, he was accused of sexual harassment by a female soldier and was later sent home.

It has been announced that during a search of Johnson’s home on Friday that bomb-making material, assault rifles, bullet-proof vests and ammunition were discovered. There was also a written manifesto outlining shooting techniques and tactics.

Johnson was eventually killed when police forces used explosives that were placed by a robot in order to end the stand-off in a building where he retreated to.

Dallas has responded to the horrific event with an outpouring of support for the police force, with The Dallas Police Department headquarters being covered with flags, candles, flowers, balloons as well as messages of support.