Dallas Police Chief David Brown. (screenshot via Twitter)

2:54 p.m. PDT Friday: NBC 5 has provided some chilling details into the standoff between police officers and alleged shooter Micah Xavier Johnson. According to a law enforcement source, Johnson was “laughing and singing and not at all anxious during the standoff at the El Centro College building.” He also reportedly “told police he had specifically been training for this event and working out in preparation for Thursday night.” NBC 5 also notes that he was wearing a “military-style bulletproof vest” and carrying a “military-style rifle.” Additionally:

Johnson at first said that he only wanted to talk to black police officers – he said he didn’t want to have anything to do with white people. He shared police conspiracies and his dislike for police officers, a law enforcement source said.

12:49 p.m. PDT Friday: Mourning continues for the police officers who lost their lives in Thursday night’s shooting:

Meanwhile, presidential candidates Hillary Clinton and Donald Trump have canceled campaign events Friday because of the tragedy. Clinton expressed her mourning for the policemen “shot while doing their sacred duty to protect peaceful protesters,” while Trump offered his prayers not only for the officers but also stated that the “senseless, tragic deaths of two people in Louisiana and Minnesota” are a reminder of “how much more needs to be done.”

11:13 a.m. PDT Friday: The Associated Press named the suspect in the shooting as 25-year-old Micah Johnson, a Dallas-area resident. Johnson was reportedly an Army veteran who fought in Afghanistan.

8:09 a.m. PDT Friday: Members of the Congressional Black Caucus have called for a vote on gun control legislation, saying, “If we fail to act, this will be a long, hot summer.”

“Republicans — what on earth? — why are you recalling and not giving us a debate on gun violence?” said Rep. G.K. Butterfield, a North Carolina Democrat and chairman of the Congressional Black Caucus. “Why not give us a hearing? Give us an up-or-down vote on our legislation on gun violence — why?”

Here’s footage from Dallas police Chief David Brown’s press conference:

6:41 a.m. PDT Friday: Three unidentified suspects are in police custody, and one suspect was killed. Six police officers and two civilians were injured in the attack, in addition to the five police officers who were killed.

The Guardian’s Oliver Laughland wrote: “The shooting marked the deadliest attack on law enforcement since 9/11 and threatened to inject yet more tension into the already divisive debate over racial disparities in US policing.”

A short video report by The Guardian brings readers up to date.

6:34 a.m. PDT Friday: Both Mayor Rawlings and Chief Brown emphasized to reporters that the protests were peaceful until the “ambush.” “We believe” in free speech, Rawlings said. Brown said the shooter, firing in the En Centro parking garage, told police he was not affiliated with any group and that he carried out the attack alone.

According to The Guardian, Brown said Americans won’t diminish their democracy out of fear of these kinds of attacks. “Our country is better than that.”

On the subject of relations between police and the public, Brown said, “We’re hurting. Our profession is hurting. Dallas officers are hurting. We are heartbroken.” He added, “All I know, is this must stop, this divisiveness between our police and our citizens.” And, “We don’t feel much support most days. Let’s not make today most days.”

6:11 a.m. PDT Friday: In a press conference, police Chief David Brown said the unnamed suspect who was shooting at police, and with whom police were negotiating, told police that he wanted to kill officers and “white people.”

Brown said:

The suspect said he was upset about Black Lives Matter. He said he was upset about the recent police shootings. The suspect said he was upset at white people, the suspect said he wanted to kill white people, especially white officers.

Responding to a question about the suspect’s mental state, Brown said:

He wanted to kill officers, and he expressed killing white people. He expressed killing white officers. He expressed anger for Black Lives Matter.

None of that makes sense. None of that is a legitimate reason to do harm to anyone.

5:18 a.m. PDT Friday: Asked how a suspect was killed, Mayor Rawlings said: “There seemed to be gunshot some time after the explosion took place. We are going to have all that and make sure we have our I’s dotted and T’s crossed at our press conference this morning. We had a device that we robotically sent in – an explosive device. He was being very very bellicose … saying he was going to take everybody out. He threatened other bombs. We felt that was the safest way to get him and it was.”

5:08 a.m. PDT Friday: Extensive searches were made for explosives, but no bombs were found, said Maj. Max Geron of Dallas police. One of the suspects told police bombs had been left “all over the place.” The suspect was later reported to have committed suicide.

5:01 a.m. PDT Friday: Mayor Rawlings said police had “taken out” a suspect via an explosive device in a parking garage. “We were very happy when we were able to take this one suspect out,” he said.

President Obama condemned the killings as “a vicious, calculated and despicable attack on law enforcement.” He added: “Anyone involved in these senseless murders will be held fully accountable. Justice will be done.”

Here’s Obama’s statement, delivered at the start of a NATO summit in Warsaw, Poland:

I spoke this morning with Mayor Rawlings of Dallas to convey the deepest condolences of the American people. I told him that the federal government will provide whatever assistance Dallas may need as it deals with this tremendous tragedy.

We still don’t know all the facts.

What we do know is that there has been a vicious, calculated and despicable attack on law enforcement. Police in Dallas were on duty doing their jobs keeping people safe during peaceful protests. These law enforcement officers were targeted and nearly a dozen officers were shot. Five were killed, other officers and at least one civilian were wounded; some are in serious condition. We are praying for their recovery.

As I told Mayor Rawlings, I believe I speak for every single American when I say we are horrified over these events and we stand united with the people and the police department in Dallas.

According to police, there are multiple suspects. We will learn more undoubtedly about their twisted motivations.

Let’s be clear: There is no possible justification for these kinds of attacks or any violence against law enforcement.

The FBI is already in touch with the Dallas police and anyone involved in these senseless murders will be held fully accountable. Justice will be done.

I will have more to say about this as the facts become more clear. For now, let me just say that even as yesterday I spoke about our need to be concerned as all Americans about racial disparities in our criminal justice system, I also said our police have an extraordinarily difficult job.

The vast majority of them do their job in outstanding fashion. I also indicated the degree to which we need to be supportive of those officers who do their job each and every day, protecting us and protecting our communities. Today is a wrenching reminder of the sacrifices they make for us.

We also know when people are armed with powerful weapons, unfortunately, it makes attacks like these more deadly and more tragic.

In the days ahead, we will have to consider those realities as well.

In the meantime, today, our focus is on the victims and their families. They are heartbroken. The entire city of Dallas is grieving. Police across America, it is a tight-knit family, feels this loss to their core and we are grieving with them.

I ask all Americans to say a prayer for these officers and their families. Keep them in your thoughts. As a nation, let’s remember to express our profound gratitude to our men and women in blue, not just today, but every day.

4:52 a.m. PDT Friday: Dallas Mayor Mike Rawlings has confirmed that the suspect in a standoff with police has died, and added that he was told by experts that two civilians and 12 officers were shot.

Another officer killed in the attack was identified by family as Patrick Zamarripa.

4:43 a.m. PDT Friday: A fifth police officer shot in the attack has died. Police have released Mark Hughes. Hughes’ brother, Corey Hughes, was one of the organizers of the protest. He had told media that his brother was not involved in the attack. Mark Hughes told media he “could easily have been shot” and said he was not satisfied with a police apology after getting death threats on social media.

Brent Thompson, seen below, was one of the officers killed in the attack. He is the first DART officer to be killed in the line of duty. The four other slain officers have not been named.

10:33 p.m. PDT Thursday: “Currently we are in negotiations with a suspect involved in these shootings,” Chief David Brown of the Dallas Police Department announced in a press conference. A standoff with the suspect, whom Chief Brown said was shooting from the second floor of a parking garage, was still underway.

A woman “who was in the same area” as the suspect was in custody, and two people who had been riding in a Mercedes containing a camouflage bag were also being detained. Police had exchanged gunfire with the suspect over the last 45 minutes, and the suspect told officers “the end is coming” and “that there are bombs all over the place — meaning downtown,” Brown said.

10:21 p.m. PDT Thursday: The man whose photo was circulated earlier in the evening in connection with the Dallas shooting has been identified as Mark Hughes. He reportedly turned himself in to authorities after his photo was publicized, and a video taken around the time the gunfire began placed him on ground level. As the website Heavy reported Thursday night, Hughes had legally brought a rifle to the protest:

While police still say he is a “person of interest,” his family and others quickly took to social media and local news stations to say the man was not involved. A man who said he is the brother of the man seen in the photos told CBS DFW the man was not the shooter. He [the man questioned] has been identified on Twitter as Mark Hughes, the brother of the protest’s organizer.

The man’s family said he was carrying the rifle, which is legal in Texas, to exercise his Second Amendment rights.

… The brother of the “person of interest” told CBS DFW his brother gave the gun to police after the shooting began, because he was afraid of being mistaken for a suspect. Police believe two gunmen were involved in the shooting, and shot the officers from elevated positions during the rally.

Below are snippets of discussion about Hughes from the Twitterverse — links contained in the tweets lead to footage showing Hughes on street level:

10:09 p.m. PDT Thursday: According to Dallas police Chief David Brown, the officers were shot “ambush style” and shot in the back.

The Dallas Morning News also shared this photo of mourning:

10:02 p.m. PDT Thursday: More video footage of the chaos and apparent gunshots heard in downtown Dallas:

Warning — the video below shows graphic violence:

Heavy security has since entered the area:

9:57 p.m. PDT Thursday: The police have provided additional information about potential suspects:

The Associated Press adds that seven officers were injured in addition to the four who have died.

9:45 p.m. PDT Thursday: Earlier this evening, the Dallas Police Department reported a shooting at a rally in the city. The rally was reportedly being held to protest the recent deaths of Alton Sterling and Philando Castile and draw attention to racial disparities in the criminal justice system. The Dallas Police Department stated that two snipers positioned on rooftops shot at police present at the rally:

According to CNN, the rally was being held “about two blocks from Dealey Plaza” and bystanders recounted hearing gunshots. “Whoever was shooting had an assault rifle—and I know guns,” said one witness. “The shots were in rapid succession.”

While initial reports stated that three officers had been killed and several others were wounded, the Dallas Police Department soon tweeted that a fourth officer had died. It also stated that two people were in police custody:

Though police initially described one of those in custody as a suspect, going so far as to publicize his photo, they now describe him as “a person of interest.”

More updates will be posted as the story develops.

—Posted by Emma Niles, Kasia Anderson and Alexander Reed Kelly.

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