Micah Johnson's mother, Delphine Johnson, told TheBlaze website in an interview that her son wanted to be a police officer as a child. His six years in the Army Reserve, including a tour in Afghanistan, were "not what Micah thought it would be ... what he thought the military represented, it just didn't live up to his expectations." According to the military lawyer who represented him, Johnson was accused of sexually harassing a female soldier while deployed.
His father, James Johnson said haltingly and through tears: "I don't know what to say to anybody to make anything better. I didn't see it coming."
The black 25-year-old fatally shot five officers in Thursday's attack while hundreds of people were gathered in downtown Dallas to protest recent fatal police shootings, and wounded at least nine officers and two civilians.
Dallas Police Chief David Brown clarified Monday where Johnson was killed with a bomb delivered by a remote-controlled robot, saying that it happened on the second floor of El Centro College, not a parking garage as authorities previously described. Brown did not provide more details, including the locations of the negotiations that came before the bomb.
WATCH: "DALLAS STRONG" VIGIL HELD FOR VICTIMS, FAMILIES
The police chief again defended the decision to use the robot, saying he had "already killed us in a grave way, and officers were in surgery that didn't make it."
"This wasn't an ethical dilemma for me," Brown said. "I'd do it again ... to save our officers' lives."
Authorities have said Johnson had plans for a larger assault, possessed enough explosive material to inflict far greater harm and kept a journal of combat tactics. Eleven officers fired at Johnson and two used an explosive device, Brown said, adding that the investigation will involve more than 170 hours of body camera footage and "countless hours" of dashcam video.
"Bravery is not a strong enough word to describe what they did that day," Brown said of officers' response to Thursday's events.
Surgeons at Parkland Memorial Hospital spoke Monday afternoon about treating some of the victims. Dr. Brian H. Williams, who is black, said: "It weighs on my mind constantly (that he was unable to save the officers ... It has to stop. Black men dying and being forgotten. People retaliating against the people sworn to protect us."
PHOTOS: Shots fired during downtown Dallas protest
Dr. Alex Eastman, the director of the hospital's trauma center who also is a deputy medical director with the city's police department, said the shootings "rocked some guys to their core that I thought were unshakable."
Brown provided details of authorities' negotiations with police Sunday on CNN's "State of the Union," saying Johnson laughed at authorities, sang and at one point asked how many officers he had shot. Johnson insisted on speaking with a black negotiator and wrote "RB" and other markings in blood on the wall - the meanings of which were unclear and being looked at by investigators, Brown said.
Federal agents are trying to trace the origin of the weapons used by Johnson, including a military-style semi-automatic rifle. About 30 agents are involved in identifying bullet casings, said William Temple, the Dallas agent in charge for the Bureau of Alcohol, Tobacco, Firearms and Explosives.
Johnson's time in the Army was marked by a sexual harassment accusation in May 2014 while in Afghanistan. The Army sent him stateside, recommending an "other than honorable discharge" - which is "highly unusual" because counseling is usually ordered before more drastic steps are taken, said Bradford Glendening, the military lawyer who represented him.
"In his case, it was apparently so egregious, it was not just the act itself," Glendening told The Associated Press. "I'm sure that this guy was the black sheep of his unit."
According to a court filing, the victim said she wanted Johnson to "receive mental help," and sought a protective order to keep him away from her and her family. Johnson was ordered to avoid all contact with her. It was unclear whether Johnson ever received counseling.
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The shootings just a few blocks from where President John F. Kennedy was slain in 1963 marked the deadliest day for U.S. law enforcement since the Sept. 11, 2001, terrorist attacks.
This attack began during protests over the police killings of Philando Castile, who was fatally shot near St. Paul, Minnesota, and Alton Sterling, who was shot in Baton Rouge, Louisiana, after being pinned to the pavement by two white officers. Video from Dallas showed protesters marching along a downtown street about half a mile from City Hall when shots erupted and the crowd scattered, seeking cover.
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Two El Centro students hid in the building overnight, Brown said, because they were afraid to come out until the shooting stopped. Police got them out of the building Friday morning. Two officers from El Centro were injured.
A memorial service is planned Tuesday for the five officers who were killed, with President Barack Obama, Vice President Joe Biden and former President George W. Bush and his wife, Laura, slated to attend.
Texas Gov. Greg Abbott announced Monday that he will not be able to make it because he'll be undergoing skin grafts on his feet after suffering second- and third-degree burns on his feet and both legs below the knees. His wife, Cecilia Abbott, will take his place.
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