He shot the officers at the end of a protest against the recent killings by police of Alton Sterling in Baton Rouge, Louisiana, and Philando Castile in Falcon Heights, Minnesota.

He then fled in the van to nearby Hutchins, Texas (10 miles (16 km) south of Dallas), where he stopped in the parking lot of a Jack in the Box franchise.

[19] A protest was organized in Dallas by the Next Generation Action Network in response to the killings of two men, Alton Sterling and Philando Castile, by police officers in Louisiana and Minnesota, respectively, days before.

[6][22] About 20 to 30 open-carry gun rights activists joined the protest march, some wearing gas masks, bulletproof vests, and fatigues, according to Dallas Police Chief David Brown.

[26] Around 8:58 p.m. Johnson parked his SUV sideways on Lamar Street, in front of the east entrance to the college, at Building A, and left the vehicle hazard lights blinking.

Corporal Bryan Shaw was shot in the stomach underneath his bulletproof vest, while Officer John Abbott was hit by flying glass in the legs.

[34] Hearing the shattering glass, one of the injured campus officers, Corporal Shaw, made his way through the building and discovered a trail of blood leading to a stairwell.

[26][35] Afterwards, Johnson made his way along a mezzanine between the school's second-floor dining area and third-floor library, but came onto a dead end of windows facing down onto Elm Street.

[36] He was in an area filled with offices and the school's computer servers, with only two doors leading to where he was positioned, and a hallway about 30 feet (9.1 m) long separating him from SWAT members.

[37] The body camera footage shows Senior Corporal Matt Banes expressing concern that the bullets Johnson fired on the second floor were easily penetrating the drywall, making it impossible for the negotiators to find safe cover, and posing a risk to any students who might have remained in the building.

According to Chief Brown, Johnson appeared delusional during his standoff; "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."

[37] Senior Corporal Jeremy Borchardt and others ultimately arrived at the idea to use a bomb disposal remote control vehicle armed with about 1 pound (0.45 kilograms) of C-4 explosive.

[37] Police had initially located Johnson within the college by following a trail of blood he had left behind as he climbed to the second floor, bleeding from a wound he had sustained on Lamar Street.

She specifically recalled one incident where Johnson punched out a car window over her leaving for college and severed an artery, then forced her to bring him to a hospital for treatment.

However, Johnson claimed that he punched out the window when the soldier missed a movie they planned to see together, and added that he had been under stress from his job and turbulent home life at the time.

Police said they had found no direct ties between Johnson and Black Lives Matter protesters, and believed the suspect had been planning an attack for some time and acted on his own.

[99] According to an employment application made by Johnson seven months before his death, he worked in a Jimmy John's sandwich shop in north Dallas beginning in 2010, and took a position as a quality assurance worker at a Garland, Texas, truck plant in 2012.

[88] The Veterans Health Administration released documents in August 2016 showing that Johnson had symptoms for post-traumatic stress disorder (PTSD) following his return from Afghanistan.

Johnson had sought treatment for anxiety, depression, and hallucinations, once telling doctors that he had experienced nightmares after witnessing fellow soldiers dying in explosions.

Johnson also said that he would hear voices and mortars exploding; and that after returning to the U.S., he would be paranoid, suffer from lower back pain, and experience panic attacks a few times per week.

[112][113] In 2014, Johnson received training and instruction at a private self-defense school that teaches tactics such as "shooting on the move" (i.e., quickly firing, then changing position and resuming gunfire).

[116] Investigators believed that he began amassing his arsenal around the same time, stockpiling guns and gathering chemicals and electronic devices and PVC piping needed to build explosives.

"[48] Chief Brown said that recovered evidence pointed to Johnson practicing detonations and having enough explosive material to cause "devastating effects" throughout Dallas and the North Texas area.

[137] The then-president of the Dallas Police Association, Mike Mata, stated that due to the criticism of militarization of police, someone within the DPD's chain of command ordered the officers assigned to the protest to not wear military-style bulletproof vests because they did not want the officers to look too "militaristic, aggressive" and instead to wear standard issue kevlar vests, which were not able to protect against the rifle rounds Johnson fired.

[144][145] Chief Brown said that police efforts to identify the gunman were made more difficult by the presence of up to thirty civilians openly carrying rifles during the protest, which is legal in Texas.

In an interview after the shooting, Dallas Mayor Mike Rawlings said that he supported changing state law to restrict the public carrying of rifles and shotguns so that the police could distinguish between suspects and civilians more easily during crises.

[146][147] Dallas Observer noted several similarities between Johnson and Mark Essex, a discharged U.S. Navy sailor and Black Panther who committed two attacks against White civilians and police officers on December 31, 1972, and January 7, 1973, in New Orleans.

Demetrick Pennie, represented by lawyer Larry Klayman, filed a lawsuit in the U.S. District Court for the Northern District of Texas against 17 people—including Louis Farrakhan, the Nation of Islam, Sharpton, the National Action Network, Black Lives Matter, DeRay Mckesson, Malik Zulu Shabazz, the New Black Panther Party, George Soros, President Barack Obama, Eric Holder, Hillary Clinton, and Jesse Jackson—blaming them for the attack and seeking damages of over $500 million.

[41][42][43][44][45] The decision to attack Johnson with a robot was made after it was concluded that the heavily armed assailant had secured himself behind a corner at the end of a hallway, with no safe way for police to rush him or reach him with a sniper.

"[169] Texas Lieutenant Governor Dan Patrick attributed the violence to individuals on social media, "former Black Lives Matter protesters", and others with anti-police views,[170] later expressing regret for his statement.