A picture is emerging of Dallas police shooter Micah Johnson that points to a possible online radicalization or, at least, encouragement to murder white policemen.

Johnson visited and liked several violent racist extremist Facebook pages in the weeks prior to his killing spree.

CNN:

The message was clear. One day before Dallas police officers were gunned down, the African American Defense League was telling anyone reading its Facebook page it was time to act.

The message delivered at 9:47 a.m. Wednesday came after news broke of yet another killing of a black man by a white police officer. Philando Castile was killed in the front seat of his car after being pulled over for a broken taillight outside Minneapolis.

The message from the African American Defense League left little up for interpretation.

"The Pig has shot and killed Alton Sterling in Baton Rouge, Louisiana!: You and I know what we must do and I don't mean marching, making a lot of noise, or attending conventions. We must "Rally The Troops!" It is time to visit Louisiana and hold a barbeque. The highlight of our occasion will be to sprinkle Pigs Blood!"

The apparent author of that post, Mauricelm-Lei Millere, has so far not responded to CNN's request for comment. But from his Facebook page, CNN has discovered the killer of five Dallas police officers had visited and "liked" the AADL's site.

Micah Johnson's online history shows he followed dozens of sites that focused on injustices committed on the black community. He visited and liked several websites dedicated to Black Lives Matter and the New Black Panthers, along with the Nation of Islam and the Black Riders Liberation Party, two groups the Southern Poverty Law Center considers hate groups.

Dallas police chief: Shooter had bigger plans

One friend who spoke to CNN said Johnson was obsessed with the plight of blacks in the United States and would repeatedly watch the now 25-year-old videotaped beating of Rodney King.

"He was an expert on the history of the Martin Luther King assassination," the friend said. "And he studied Malcolm X."

The friend, who did not want to be named, also said Johnson had issues controlling his temper. "He was a good black man with a little bit of an anger problem."

A "little bit of an anger problem"?  Tell the widows and fatherless children of the dead cops that the "little anger problem" was the cause of their suffering at the hands of a "good black man."

I reject the notion that Johnson was "radicalized" online.  He was already a radical and was feeding his hate by visiting websites that reflected his warped view of whites.  But there's a pretty good possibility that he was specifically encouraged by hate groups to kill white policemen.  That would be a crime and should result in the arrests of those who advocated killing police and the shutting down of the sites in question. 

Can someone who is mentally ill plan and execute a military-style operation with precision, as many experts are saying Johnson was able to do?  President Obama and others have been pushing the idea that Johnson was crazy, not a virulent racist.  If he was mentally ill, he was perfectly capable of functioning at a high level to carry out his plan that may have been born on the internet.