The man who fatally shot five police officers in Dallas may have had plans for a wider attack, the city's police chief said Sunday. Dallas Police Chief David Brown provided new details about the tense two-hour standoff that police had with the gunman before he was killed.
"We're convinced that this suspect had other plans," Brown told CNN, adding that the shooter "thought that what he was doing was righteous and believed that he was going to target law enforcement and make us pay for what he sees as law enforcement's efforts to punish people of color."
Investigators are looking at where former Army reservist Micah Xavier Johnson, 25, was in the days and hours leading up to the attacks. According to two law enforcement officials close to the investigation, Johnson's mother has been cooperating with authorities to help them piece together what happened.
Officials have searched a home Johnson shared with his mother in Mesquite, Texas, just outside Dallas, but they tell NPR it is unclear how much time Johnson actually spent at that residence and whether he may have other apartments in the area that they haven't yet discovered.
In the search of the house in Mesquite, officials say they found bomb-making materials, detonators, ammunition, bulletproof vests and some journal writings that suggest Johnson had been contemplating violence against police for some time. The materials suggest that the protest on Thursday night just happened to provide him with an opportunity to carry out those plans.
Law enforcement sources tell NPR that Johnson drove his mother's car to the protest. Police and demonstrators had originally agreed that the protest would be static, in one place, but then people spontaneously started marching. This sent police scrambling ahead of them to block traffic as they went along.
Investigators say they now believe that Johnson essentially shadowed the march, driving from street to street, and then parked the car and went to higher ground where he could get a better vantage point on police. Once he was in position, he opened fire.
Investigators tell NPR they also are starting to look at Johnson's online history, and have mirrored the hard drive on his computer to see what they might discover there. They haven't ruled out that he had accomplices, or at least people who might have helped him indirectly. There was, for example, a manifesto of sorts with his picture on Instagram that was posted after the attack began. Officials haven't yet ruled out that it was something either he posted during the attack or had instructed an accomplice to post should he be killed.
Now that officials have his computer, that could shed some light on that part of the investigation.
RENEE MONTAGNE, HOST:
The Dallas shooter who killed five police officers last week may have had plans to launch a more deadly attack. That's according to Dallas Police Chief David Brown, who provided new details to CNN.
DAVID BROWN: 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 law enforcement - target law enforcement and make us pay for what he sees as law enforcement's efforts to punish people of color.
MONTAGNE: That's the police chief of Dallas. NPR's Dina Temple-Raston has been following the investigation and joins us with the latest now. Good morning.
DINA TEMPLE-RASTON, BYLINE: Good morning.
MONTAGNE: What else are law enforcement officials finding?
TEMPLE-RASTON: Well, we spoke to two law enforcement officials close to the investigation who are trying to piece together what 25-year-old former Army reservist Micah Xavier Johnson was doing in the days and weeks leading up to the attacks. Investigators have searched a house Johnson shared with his mother in Mesquite, Texas, which is a Dallas suburb. And they found ammunition and detonators and explosives and journals that he wrote in. And all that evidence is one of the reasons why they believe he wanted to do something more violent. Johnson's mother, we're told, is cooperating with the police, but there's some mysteries that remain. For example, the shooter wrote cryptic messages in his own blood on the wall where he was killed. We understand from our sources that he scrawled the letters RB, and nobody knows what that stands for yet.
MONTAGNE: And that's in a garage. You know, it was in a public space.
TEMPLE-RASTON: It's in a public space, and it was written in his blood.
TEMPLE-RASTON: And apparently there were some other words that he wrote on the walls just before he died. But investigators haven't made those details public yet.
MONTAGNE: Do police now think that the shooter had not planned necessarily to attack last Thursday night, but that the protests gave him an opportunity to target police?
TEMPLE-RASTON: Exactly. We know a little bit more from our sources about what happened before he started shooting. They told us that Johnson took his mother's car to the protest. And that protest was originally supposed to be something they call a static event, meaning it all took place in one - one place. And then these demonstrators spontaneously started marching, and that wasn't something that the police had actually planned for. So they started moving from block to block to protect the protesters from oncoming traffic. And now they know - or they believe they know that Johnson was sort of shadowing the march in this car and then decided to park the car and go to higher ground and open fire.
MONTAGNE: Now, you said among the clues investigators discovered in his mother's house were journals that he had - Johnson was thought to have written. What are they getting out of those journals?
TEMPLE-RASTON: Well, our sources say the journals contain a lot of diagrams and notes on combat tactics. And they also contain sort of disjointed rants that investigators are still trying to understand. They found his computer, and they're scouring that to try to see if they can find any connections he might have with other groups. They haven't ruled out that he had some accomplices or at least people who might have helped him indirectly. For example, there was a manifesto on social media that was posted after the attack began. And they haven't determined if he's the author of that manifesto, but it certainly touched on a lot of the same themes that police have been focused on, and they haven't ruled out that either he posted it during the attack or something he had an accomplice post. And now that they have his computer, they can understand that a lot better.
MONTAGNE: And we'll obviously be learning much, much more in the coming days.
TEMPLE-RASTON: We expect so.
MONTAGNE: That's NPR's Dina Temple-Raston. Thanks very much.
TEMPLE-RASTON: You're welcome. Transcript provided by NPR, Copyright NPR.