BATON ROUGE, La. -- A deadly shooting of Baton Rouge police officers roiled the Louisiana capital on Sunday. The city and nation were already in turmoil, with tensions over race and policing reaching a head coast-to-coast.

Three Baton Rouge law enforcement officers were killed and three others wounded Sunday, less than two weeks after a black man was shot and killed by police here in a confrontation that sparked nightly protests across the city that reverberated nationwide.

A suspect described by police as a black male has been killed, according to officials. Police involved in the shooting included officers with the Baton Rouge Police Department and deputies from the East Baton Rouge Sheriffs Office.

Law enforcement officers block the entrance to the Louisiana State Police Headquarters in Baton Rouge, Louisiana, U.S. July 17, 2016. REUTERS

Here is the latest on the investigation.

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Suspect is deceased

The deceased suspect in the deadly shooting of Baton Rouge law enforcement officers appeared to have attacked police on his 29th birthday, CBS News has learned.

The suspect has been identified as a black male named Gavin Eugene Long of Kansas City, Missouri, sources confirm to CBS News. He was born on July 17, 1987.

According to a military source, Long left the Marines in 2010 with an honorable discharge. His final Marine rank was E-5 (sergeant).

Military records show he received several medals during his military career, including one for good conduct, and received an honorable discharge.

Long's last known address was in Kansas City, Missouri and law enforcement officers converged on a house there this afternoon.

Law enforcement sources tell CBS News that Long used the pseudonym of Cosmo Setepenra online. He posted at least one video on YouTube about oppression and police protests.

Screengrab from a video of a Gavin Eugene Long using the pseudonym of Cosmo Setepenra. YouTube

Long also briefly attended the University of Alabama. University spokesman Chris Bryant said Sunday evening that Long was a student for one semester in the spring of 2012.

Bryant said university police had no interaction with Long during that time.

One suspect was killed and two others might still be at large, Casey Rayborn Hicks, a spokeswoman for the East Baton Rouge Sheriff's Office, previously said. However, Louisiana state police said Sunday afternoon there is "no active shooter" in Baton Rouge.

A state police spokesman said that the two "persons of interests" who were detained earlier Sunday had been released.

Major Doug Cain said late Sunday that the individuals from Addis were questioned and released but that the investigation was still ongoing.

He said no charges were filed against them.

Cain said authorities are still looking to see if the man who opened fire on police in Baton Rouge had any help -- "indirectly, directly here or at home."

CBS News has learned that Long rented a white Chevy vehicle in Kansas City, Missouri, on July 12 and drove to Baton Rouge.

Deceased officers identified

All three of the slain law enforcement officers in Baton Rouge have been identified.

According to officials, one of them is Matthew Gerald, 41, of Denham Springs.

Gerald was a former Marine, a former Black Hawk Crew Chief in the Army. He just graduated from the BRPD Academy in March, CBS affiliate WAFB reported.

Matthew Gerald celebrated his fourth wedding anniversary just two weeks ago.

WWL-TV reported Gerald and his wife, Dechia, have a 3-year-old daughter together and that Gerald had adopted his wife's daughter from a previous relationship.

Family friend Skye Turner says Gerald was, "a good family man, good cop, loving husband."

WWL reported Gerald was a former Marine and Blackhawk crew chief in the Army and had joined the police department four months ago. Gerald was gunned down Sunday along with two other officers.

Louisiana State Rep. Ted James Sunday gave the name of the second dead officer as Montrell Jackson.

James said Jackson had a 4-month-old child.

Officers Montrell Jackson, Brad Garafola, and Matthew Gerald, all killed in Baton Rouge on Sunday, July 17, 2016. CBS affiliate WAFB

James said he knows Jackson and his family personally and spoke to the family earlier Sunday.

A spokeswoman for the East Baton Rouge Parish Sheriff's Office has identified the third officer killed as sheriff's deputy Brad Garafola.

Casey Rayborn Hicks told The Associated Press Sunday that the slain deputy was 45-years-old and had been with the sheriff's office for 24 years.

A neighbor of Garafola says he was a family man.

Rhonda Smith said Sunday evening that Garafola was never seen without at least one of his four children, who range in age from 7 to 21.

Smith says Garafola was, "the epitome of a peace officer."

Hicks also identified the injured sheriff's deputies as 41-year-old Nicholas Tullier an 18-year veteran, and 51-year-old Bruce Simmons, a 23-year veteran. Hicks says that Tullier is in critical condition while Simmons has non-life threatening injuries.

The Baton Rouge Police Department released a statement and photos of their deceased officers on Facebook.

How the events unfolded

Police responded to a report of officers shot at a location on Airline Highway near Old Hammond Highway around 9 a.m., CBS affiliate WAFB reported.

A law enforcement source told CBS News senior investigative producer Pat Milton that police were called to the location on Airline Highway, less than a mile from the Baton Rouge Police Department headquarters, after someone reported a suspicious man with a weapon.

A witness tells CBS affiliate WAFB that he saw a masked man in black shorts and shirt running from the scene where three Baton Rouge law enforcement officers were shot and killed.

Brady Vancel said the man looked like a pedestrian running with a rifle in his hand, rather than someone trained to move with a rifle.

Vancel said he'd gone to work on a flooring job on a street behind the gas station where authorities say the shooting occurred. He said he heard semi-automatic fire and perhaps a handgun.

He saw a man in a red shirt lying in an empty parking lot and "another gunman running away as more shots were being fired back and forth from several guns."

Earlier, Baton Rouge Police Cpl. L'Jean McKneely Jr. said the shooting took place outside and possibly inside the B-Quik convenience store on Airline Highway in Baton Rouge.

He said the suspect's body was found next door, outside a fitness center.

A law enforcement source in Baton Rouge tells CBS News correspondent David Begnaud one of the law enforcement officers was vacuuming his patrol car just before he was shot. Video shows him vacuuming his patrol car, leaving the car wash area, then returning after getting a report of a man with a weapon.

A second slain officer was in the convenience store just before he was shot.

The source said the gunman's movements are being described as tactical and "gifted."

"He knew exactly what he as doing," the source said.

The source said the SWAT team moved in and shot the gunman, and it was captured on surveillance video.

The source has viewed videos which are said to have captured "almost everything."

Political response to the shooting

The governor of Louisiana said the attack on law enforcement in Baton Rouge was unjustified.

Gov. John Bell Edwards told media Sunday afternoon that the gunman committed, "an absolutely unspeakable, heinous attack." Edward said the hatred has got to stop.

Republican Donald Trump is blaming a "lack of leadership" for Sunday's shooting in Baton Rouge.

Trump said in a statement posted on his Twitter and Facebook pages that "We grieve for the officers killed in Baton Rouge today."

Trump is placing the blame on a lack of leadership and is demanding "law and order."

He asked, "How many law enforcement and people have to die because of a lack of leadership in our country? We demand law and order."

Hillary Clinton released a statement on Twitter in regards to the shooting.

"Today's devastating assault on police officers in Baton Rouge is an assault on all of us," she said.

Hillary's statement on the shooting in Baton Rouge. pic.twitter.com/4a0MVF3025 — Hillary Clinton (@HillaryClinton) July 17, 2016

Attorney General Loretta Lynch, responding to the police shootings Sunday in Baton Rouge, Louisiana, said there is no place in the United States for such appalling violence.

In a statement issued Sunday, Lynch said she condemns the shooting deaths of three officers and the wounding of several others "in the strongest possible terms."

She also is pledging the full support of the Justice Department as the investigation unfolds.

The attorney general said Agents from the FBI and Alcohol, Tobacco and Firearms are on the scene, and Justice Department will make available victim services and federal funding support, and provide investigative assistance to the fullest extent possible.

Lynch said everyone's hearts and prayers are with the fallen and wounded officers, their families and the entire Baton Rouge community in "this extraordinarily difficult time."

President Barack Obama said the slayings were attacks "on the rule of law and on civilized society, and they have to stop."

He said there was no justification for violence against law enforcement and that the attacks are the work of cowards who speak for no one.

Vice President Joe Biden said on Twitter he was joining the president in condemning the attack.

I join the President in condemning today's despicable, cowardly attack in Baton Rouge. An attack on our very way of life and rule of law. — Vice President Biden (@VP) July 18, 2016

We owe these officers & families more than gratitude. We owe them a commitment as a country to stand together when hate tries to divide us. — Vice President Biden (@VP) July 18, 2016

Vice President Biden also released a statement condemning the shooting.

"Police officers are an incredible group of men and women. We owe them our gratitude and a commitment not to let others divide us," the statement read. "That's not who they were, that's not who they are."

Tense Baton Rouge

It is the fourth high-profile deadly encounter in the United States involving police over the past two weeks. The violence has left 12 people dead, including eight police officers, and sparked a national conversation over race and policing.

Baton Rouge has been tense since the July 5 shooting of a black man pinned to the ground by white police officers.

At a three-hour service Friday, mourners paid their respects to 37-year-old Alton Sterling, whose shooting outside a convenience store began a tumultuous week in race relations in America.

Last week, police arrested and identified three young people who they say plotted to kill Baton Rouge cops using guns stolen from a pawn shop. Law enforcement said at a conference they believe it to be a substantial and credible threat on police officers in the Baton Rouge area.

On Friday, grieving residents of Baton Rouge honored an appeal at the funeral of Sterling to celebrate his life rather than demonstrate about his death.

"If you want to protest, please leave now," Gary Chambers, master of ceremonies for the funeral, said at the beginning that the event at Southern University.

A steady stream of mourners filed past Sterling's casket, which was adorned with music notes and a smiling photo of the man. Sterling was selling CDs outside the Triple S Food Mart store, as he had done for years, when he was killed by police responding to a call of a man threatening someone with a gun. Police have said they found a gun in Sterling's pocket.

Sterling's death was captured on cellphone video and circulated widely on the internet. His death, along with another fatal police shooting in Minnesota last week, sparked widespread protests. Then the fatal shooting of five police officers in Dallas by a black sniper heightened tensions even more.

Sterling's death heightened tensions in Baton Rouge, where about 200 protesters were arrested over the weekend. East Baton Rouge Parish District Attorney Hillar Moore said his office reviewed initial police reports on 185 arrests between July 8-11 and determined it will not prosecute roughly 100 of those cases.

Moore said they involve protesters who were arrested only on misdemeanor charges of obstruction of a roadway or public passage. DeRay Mckesson, a prominent Black Lives Matter activist, was among them. Moore said his office is reviewing the rest of the arrests, which include allegations such as resisting arrest, carrying guns or some "act of violence."