The suspect, dressed in black and armed with a rifle, was  shot dead on Sunday morning in a gunfight with police who converged on the scene of a confrontation that Mayor Kip Holden said began as an "ambush-style" attack.
               
Two Baton Rouge Police Department officers and one sheriff's deputy were killed, and one sheriff's deputy was critically wounded. Another officer and one other deputy suffered less severe wounds. Col. Mike Edmonson, superintendent of the Louisiana State Police, told a news conference the gunman was believed to have acted alone.
               
It was not immediately clear whether there was a link between the bloodshed and unrest over the police killings of two black men in questionable circumstances this month-Alton Sterling, 37, in Baton Rouge on July 5, and Philando Castile, 32, near St. Paul, Minnesota, on July 6.
               
Police did not identify the suspect, but a US government official told a news agency he was Gavin Long, of Kansas City, Missouri. Long, who was black, was reported to be 29 years old.
               
According to Pentagon, Long served in the Marines from 2005 to 2010, achieving the rank of sergeant.A data network specialist, he was deployed to Iraq from June 2008 until January 2009, earning several medals and commendations.
               
Authorities declined to offer a possible motive for the attack in Louisiana's capital, a city with a long history of distrust between African-Americans and law enforcement, which was inflamed by Sterling's death.
               
Social media postings linked to an individual named Gavin Long and a Kansas City address cordoned off by police included a July 10 YouTube video saying he was fed up with mistreatment of blacks and suggesting only violence and financial pressure would bring change. He also said he was speaking from Dallas after going there to protest.
               
"It's only fighting back or money. That's all they care about," he said to the camera. "Revenue and blood, revenue and blood, revenue and blood." In a separate video, he hinted that should "anything happen" to him, he wanted viewers to know he was "not affiliated" with any particular movement or group.
               
"I'm affiliated with the spirit of justice, nothing more nothing less," he said. "I thought my own thoughts, I made my own decisions."A second government source, speaking on condition of anonymity, said an emergency 911 call may have been used to lure Baton Rouge police.

Edmonson said several officers came under fire as police responded to a report of a man  dressed in black standing behind a store holding a rifle.
               
In the ensuing pandemonium caught on a recording of emergency radio traffic, police repeatedly report: "Officer down" and "deputy down" as officers swarmed the area, ultimately confronting the gunman. The episode was over in about eight minutes.
               
Killed were Montrell Jackson, 32, a new father who had served for 10 years with the Baton Rouge Police, Matthew Gerald, 41, a newly minted officer with a military background, and Sheriff's Deputy Brad Garafola, 45, a father of four.
               
President Barack Obama condemned the attack, vowing justice would be done and calling on Americans to focus on unity.
               
"We as a nation have to be loud and clear that nothing justifies violence on law enforcement," Obama said in televised remarks."We need to temper our words and open our hearts, all of us."
               
Louisiana Gov. John Bel Edwards called the shootings an "unspeakable, heinous attack" that served no purpose.
               
"There simply is no place for more violence. That doesn't help anyone, it doesn't further the conversation, it doesn't address any injustice, perceived or real," he told reporters.
               
Obama has sought to balance concerns about police abuses, largely against African Americans, while paying tribute to fallen officers. He attended a service last week for the five Dallas police officers killed by a black former soldier who opened fire at the end of a protest on July 7, and denounced the Sterling and Castile slayings.
               
Those killings and the reprisal attack on Dallas police by a suspect found to have embraced militant black nationalism renewed tension over racial justice and guns just as America's presidential campaign went into high gear. The Dallas gunman, Micah Johnson, 25, was killed by police deploying a bomb-carrying robot.
               
The violence has also heightened security concerns, notably in Cleveland and Philadelphia, hosts to this week's Republican National Convention and next week's Democratic National Convention, respectively, which are expected to formally nominate Donald Trump and Hillary Clinton for the Nov. 8 election. "We demand law and order," Trump said on Facebook on Sunday.
               
Clinton, in a statement, urged Americans to "stand together to reject violence and strengthen our communities."
               
The head of a Cleveland police union, Steve Loomis, said he was concerned about copycat shootings and called on Ohio Governor John Kasich to declare a state of emergency and suspend laws allowing for the open carry of firearms during the Republican convention. A Kasich spokeswoman said the governor did not have the power to suspend the open-carry law.

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