BATON ROUGE, La. – A decorated ex-U.S. Marine sergeant has opened fire on police in Baton Rouge, Louisiana, killing three officers.

The incident comes nearly two weeks after the fatal police shooting of a black man there sparked nationwide protests, one of which was shattered by the massacre of five Dallas policemen.

The suspect, dressed in black and armed with a rifle, was himself shot to death minutes later in a gunfight with police who converged on the scene of a confrontation that Mayor Kip Holden said began as an “ambush-style” attack on officers.

Two Baton Rouge Police Department officers and one sheriff’s deputy were killed, and one sheriff’s deputy was critically wounded. Another police officer and one other deputy suffered less severe wounds and were expected to survive.

Colonel Mike Edmonson, superintendent of the Louisiana State Police, told a news conference the gunman was believed to have acted alone, contrary to early reports that police may have been looking for other shooters.

It was not immediately clear whether there was a link between Sunday’s bloodshed and unrest over the police killings of two black men under questionable circumstances earlier 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 name the suspect. But a U.S. government official told Reuters the gunman was identified as Gavin Long, of Kansas City, Missouri. Long, who was black, was reported by other media to be 29 years old.

According to Long’s military record, released by the Pentagon, he served in the Marines from August 2005 until August 2010, achieving the rank of sergeant. Listed as 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 Sunday’s attack in Louisiana’s capital, a city with a long history of distrust between African-Americans and law enforcement that was further inflamed by Sterling’s slaying.

Social media postings linked to an individual named Gavin Long and a Kansas City address cordoned off by police on Sunday included a YouTube video saying he was fed up with mistreatment of blacks and suggesting only violence and financial pressure would bring about change. He also said he had been to Dallas to join in the protests there.

“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.”

– Reuters