Law enforcement officials said Monday that they believe the gunman who fatally shot three patrol officers in Baton Rouge Sunday morning intended the ambush as payback for a series of highly-publicized police shootings in the city and Minnesota, closely mirroring an almost indentical fatal ambush of five officers in Dallas 9 days earlier.

Police Monday idenfified the gunman as Gavin Long, an African-American and former U.S. Marine from Kansas City, Missouri. According to the website, Heavy.com, Long often railed against white supremacy and racism on his social media posts. The shooting occurred on his 29th birthday, just days after he exhorted African Americans to "fight back" on his Facebook page, the website said.

Mike Edmonson, superintendent of the Louisiana State Police, said Monday that an emergency call at about 8:40 a.m. reported a man dressed in all black “carrying a weapon, carrying a rifle.” Two minutes later, shots were reported fired, and two minutes after that there were reports that officers were down. By 8:48 a.m., Long was dead following an exchange of gunfire with officers on the scene. Three officers were also dead, and another three critically wounded.

Long told the Associated Press Monday that the gunman was “certainly seeking out police” and described the shooting as an “ambush.” A spokesman confirmed his remarks in a press conference.

Though Long endorsed the nationwide protests against police brutality on his social media accounts, he also made clear he was not part of any specific group or movement, although law enforcement officials told reporters Monday that detectives found on Long´s body a card identifying him as a member of a black nationalist sect. The son of the organization´s founder, however, told the Washington Post that he didn’t know Long and that the group doesn’t espouse violence.

According to military records obtained by reporters, Long served in the U.S. Marines for five years, from August 2005 to August 2010, and was assigned to units in Miramar, California, and Okinawa, Japan. CBS News reported that Long left the Marines with an honorable discharge in 2010 with the rank of sergeant and was deployed once to Iraq from June 2008 to January 2009, but did not experience direct ground combat.

According to Heavy.com, he used the name Cosmo Setepenra as a pen name for his self-published books, and his personal blog.

“Violence is not THE answer (its a answer), but at what point do you stand up so that your people dont become the Native Americans…EXTINCT?,” he wrote on Twitter on July 13, according to Heavy.com

No ties to Louisiana have been found.

The slain police officers have been identified as Sheriff´s Deputy Brad Garafola, and Officers Matthew Gerald and Montrell Jackson, who was, like Long, an African American. Gerald was also a veteran.

Less than a week ago, Jackson took to Facebook to express how physically and emotionally stressed he had been as unrest erupted in his city after the July 5 killing of Alton Sterling by white police.

"I swear to God I love this city, but I wonder if this city loves me. In uniform I get nasty, hateful looks and out of uniform some consider me a threat. ... These are trying times. Please don't let hate infect your heart," he said in his post on July 8.

Long´s social media trail was significant, and he wrote repeatedly that black people had to physically resist police violence, saying that sometimes it was necessary “to go to war.” After five Dallas police officers were gunned down earlier this month by a man who authorities said was angered by police killings, Long posted a video on YouTube saying that he was “not gonna harp on that … it’s justice.”