Between the cryptic message written in his own blood and the amount of ammunition located inside his home, Micah Johnson may have been "planning something bigger" than the fatal attack that killed five Dallas police officers on July 7, authorities said.
Before he was killed, Johnson, an Army reservist, had reportedly started to write a message using his own blood during the police standoff.
"He wrote some lettering in blood on the walls, which leads us to believe he was wounded on the way up the stairwell," said Dallas Police Chief David Brown. "And where we detonated the device to end the standoff, there was more lettering written in his own blood."
Although most of the markings were reportedly not legible, the initials "RB" stood out. Investigators said they believe Johnson meant to write "RBG," the name given to the Pan African flag, which is also considered to be a Black Power symbol.
"There's lots of possibilities but RBG makes the most sense given Johnson's Black Power interests and what motivated him to carry out these attacks," a source said, as reported by the Daily Mail. "Maybe he was too weak, or just didn't get time to finish writing it."
Upon investigating Johnson’s home and finding "a bunch of explosive materials" and a "personal journal of combat tactics," authorities said they believe he was planning a larger attack that may have been pushed up due to the deaths of Alton Sterling and Philando Castile.
"I think that target of opportunity is what drove him as far as timing," a law enforcement source told WFAA.
Prior to the deadly attack, federal agencies had known nothing about Johnson. There is reportedly no indication that anyone else was involved in the attack.
"The suspect had been practicing explosive detonations," Brown told CNN. "The materials were such that it was large enough to have devastating effects throughout our city and our North Texas area. We’re convinced that this suspect had other plans and thought that what he was doing was righteous and believed that he was going to [...] make us pay for what he sees as law enforcement’s efforts to punish people of color."
President Barack Obama praised the Dallas Police Department as a leader in law enforcement reform, as reported by Yahoo.
"That’s part of why it’s so tragic that those officers were targeted in Dallas, a place that because of its transparency and training and openness and engagement has drastically brought down the number of police shootings," Obama said.