Dallas police defend use of robot-bomb

Johnson shot and killed five officers and wounded nine police and two civilians after a "Black Lives Matter" protest on Thursday night in Dallas. The 25-year-old suspect was killed on the second floor of the El Centro community college by a bomb delivered by remote-controlled robot, after several hours of fruitless negotiations with authorities by telephone.

It is believed to have been the first time that US police have killed a suspect in this manner. Some civil liberties advocates have raised concerns that it has created a troubling precedent.

Speaking at a news conference on Monday, Brown said that Micah Johnson, the 25-year-old suspect, had "already killed us in a grave way, and officers were in surgery that didn't make it."

He added: "This wasn't an ethical dilemma for me."

"They improvised this whole idea in about 15, 20 minutes," Brown told a news conference on Monday. "I asked the question of how much [explosives] we were
using, and I said ... 'Don't bring the building down.' But that was the extent of my guidance."

The Northrop Grumman Corp Mark5A-1 robot is usually used to inspect potential bombs. It was purchased in 2008 for $151,000 (136,000 euros) and was still functional, Brown said. A number of other police authorities around the US have similar devices.

Brown also said two El Centro students had hidden in the building during the overnight standoff, because they were afraid to come out until the shooting stopped. Police took them out of the building on Friday morning.

The police chief said that 11 officers fired weapons at Johnson and two used an explosive device.

Security ahead of presidential visit

The Dallas police chief also said that the Arlington Police Department had offered to work with the Secret Service to provide security during President Barack Obama's visit to the city later in the week, probably on Thursday.

Brown said he wanted to avoid his own officers shouldering the responsibility of security for the president due to "the fatigue factor" following the events of the last week.

In November 1963, President J.F. Kennedy was assassinated in Dallas.

Brown also said he was taking all threats as credible in the wake of the shootings. He pointed to a threat which had been received from a private Facebook page to the Dallas Police Department's page.

The parents of the suspect, James and Delphine Johnson, said they "did not see it coming." His father added "I hate what he did." They said he had returned from an Army deployment to Afghanistan a changed man.

Dallas police investigating the killings say Johnson was planning an even larger attack.

There have been continuing demonstrations in cities across America against the deaths of black men at the hands of police.

jm/msh (Reuters, AP)