Dallas police headquarters under lockdown after threat

The comments marked the third time in as many days that Obama has spoken, from a distance, about the police-involved fatal shootings of black men in Louisiana and Minnesota that were followed by a sniper attack in Dallas that killed five police officers.

More than 150 Federal Bureau of Investigation agents and analysts have descended on downtown Dallas, some from Federal Bureau of Investigation headquarters, to help the Dallas Police Department scour a 20 block crime scene – so big it make take three more days to collect evidence.

“He seemed very much in control and very determined to hurt other officers”, the police chief said.

Vice President Joe Biden will also attend the service, as will former first lady Laura Bush. The ex-president will deliver brief remarks.

Police had expected the Dallas protesters to remain in one area of the city centre, but demonstrators spontaneously chose to march in a different direction, Brown said.

Police said the Dallas ambush shooter had taunted police negotiators and scrawled on a wall in his own blood before he was ultimately killed in the standoff. Two officers were wounded, one critically.

Even as officials and activists condemned the shootings and mourned the slain officers, hundreds of people were arrested on Saturday as new protests against the use of deadly force by police flared in several U.S. cities. “We’re trying to figure out through looking at things in his home what those initials mean”, Brown said.

According to an internal police memo obtained by Eyewitness News, a group from Houston is allegedly driving to Dallas with the intent of killing more police officers.

Ultimately, he was killed by a bomb-carrying robot deployed and then detonated by police on the second story of a building where they had cornered him.

Johnson had practised military-style drills in his garden and trained at a private self-defence school that teaches special tactics, including “shooting on the move”. Police say Kemonte Gilmore flashed a handgun in the video and talked about the slayings of Philando Castile in Minnesota and Alton Sterling in Louisiana.

Other departments around the country have been receiving threats.

“I would hope that police organisations are also respectful of the frustrations that people in these communities feel and not just dismiss these protests and these complaints as political correctness”.

In suburban St. Louis, a motorist shot an officer at least once as the officer walked back to his auto during a traffic stop, police said.