The FBI on Monday launched a civil rights investigation into the fatal shooting of an unarmed black teenager by a police officer, an incident that has set off days of unrest in this St. Louis suburb and pushed the question of race and the use of lethal force again to the forefront of national discussion.

Michael Brown, a college-bound 18-year-old, was shot and killed Saturday in this small, predominantly African American city after an apparent confrontation with police. His death immediately inspired both solemn vigils and angry protests, which in recent days have left some stores looted, buildings burned and shattered glass in the streets. At least 32 people have been arrested on suspicion of looting.

The demonstrations showed no sign of abating Monday.

“He was a good boy. He didn’t deserve none of this. None of it,” said Brown’s father, Michael Brown Sr., who was one of more than two dozen relatives and friends at an afternoon news conference at the Jennings Mason Temple church near St. Louis. “We need justice for our son.”

The details surrounding Brown’s death remain unclear. But the case is recalling the racial animosity surrounding the fatal shooting of 17-year-old Trayvon Martin in Florida in 2012 and other recent altercations between African Americans and police. The Martin case drew in President Obama, who called for calm amid similar anger and noted that, if he had a son, he would “have looked like Trayvon.”

The day after a police officer shot and killed an unarmed 18-year-old Michael Brown, demonstrators held a rally and vigil in Ferguson, Mo. Looting followed. (Sarah Parnass/The Washington Post)

Obama did not comment on the case Monday during a public appearance in Martha’s Vineyard, Mass., where he is on vacation.

Brown’s family moved to hire lawyer Benjamin Crump, who represented Martin’s family after the teenager, also unarmed at the time of his death, was shot by a neighborhood watch volunteer. Appearing here, Crump called Brown’s shooting “another senseless death of another person of color.”

The National Bar Association, which represents African American lawyers and judges, has called for an investigation into the deaths of both Brown and Eric Garner, a 43-year-old Staten Island man who died in mid-July after being placed in a chokehold by a New York police officer. A thorough civil rights investigation is the only way that “the African American community’s faith in law enforcement can be strengthened,” Pamela Meanes, president of the association, said in a statement.

“The death of yet another African American at the hands of those sworn to protect and serve the community where he lived is heartbreaking,” Cornell William Brooks, president and chief executive of the NAACP, said in a statement.

In the Brown case, police say it appears that the teen was shot following a physical altercation with a police officer at his cruiser and a struggle involving the officer’s gun. But authorities have not said what resulted in Brown being shot multiple times nearly three dozen feet from the officer’s car.

Crump said witnesses have disputed the account offered by police, but he did not elaborate on what these witnesses said.

He called on anyone with a video of Brown’s death to come forward to show “exactly what happened.”

“Their baby was executed in broad daylight,” Crump said.

Cheryl Mimura, an FBI special agent in St. Louis, said that the bureau was opening an investigation into any potential civil rights violations that may have occurred.

“The shooting incident in Ferguson, Missouri this weekend deserves a fulsome review,” Attorney General Eric H. Holder Jr. said in a statement.

He said the FBI’s investigation “will supplement, rather than supplant,” the local inquiry.

“At every step, we will work with the local investigators, who should be prepared to complete a thorough, fair investigation in their own right,” he said. “Aggressively pursuing investigations such as this is critical for preserving trust between law enforcement and the communities they serve.”

Holder had already instructed attorneys in the Justice Department’s Civil Rights Division “to monitor developments relating to the shooting incident,” department spokeswoman Dena Iverson said in an e-mail to The Washington Post.

The local investigation will be conducted by the St. Louis County Police Department at the request of the Ferguson police.

Jon Belmar, chief of the county police, promised an impartial investigation, pointing out that none of his department’s officers was involved in the shooting. “I want to assure you that this is a very complicated investigation, as it should be,” he said Monday during a news conference. “A man lost his life. There’s a police officer involved in this. We need to make sure this investigation is done right.”

An autopsy of Brown showed that he was “struck several times by gunfire,” Belmar said. The autopsy was carried out on Sunday, the day after Brown was killed, and his body was returned to his family for burial.

At the news conference at the church, Brown’s mother, Lesley McSpadden, said that she had been overjoyed at the prospect of dropping her son off at college on Monday. Instead, she is planning his burial.

“That was my firstborn son. . . .Ask anyone and they’d tell you how much I loved my son.. . . I just wish I could have been there to help him, my son,” she muttered before breaking down in tears.

Brown’s grandmother, with whom he occasionally lived, could barely make it to the car afterward. She had to be carried by other family members.

“Oh, God, they took my baby,” she wailed.

The shooting and ensuing violence have drawn national attention, with every twist and turn explored on social media. There have been multiple public gatherings since Brown was killed, with protesters marching and chanting near the Ferguson police headquarters again Monday.

The looting on Sunday night was the work of only part of the crowd that had gathered to protest, Belmar said. He said the police got thousands of calls reporting shots fired, burglaries and assaults, among other things. A Wal-Mart was among the businesses looted, and a photographer for the St. Louis Post-Dispatch documented a burning convenience store.

Hundreds of police officers responded to the looting, according to the St. Louis County police. Two officers suffered relatively minor injuries. The people who were arrested could face charges of assault, burglary and larceny, a spokesman said.

Monday morning, the sites where rioting occurred were covered with graffiti, broken glass and debris.

Belmar said Sunday that a Ferguson police officer “had an encounter” with Brown and another person Saturday. At some point, the officer reportedly was pushed back into his car and “physically assaulted,” the chief said.

There was a struggle over the officer’s weapon, which was fired once in the car, Belmar said. Following that, the officer got out of the car and fired at the teenager multiple times. Brown was killed about 35 feet from the officer’s car, Belmar said.

The officer involved has been placed on paid administrative leave. His name has not been released.

There are still very few publicly released details of the shooting, but many civil rights leaders and family members have focused on how Brown was dressed at the time of the incident. According to reports, he was wearing cargo shorts, flip-flops and a T-shirt. He was unarmed.

“From what I’m told he had on, how would a trained policeman even feel that he could have been bearing arms?” said the Rev. Al Sharpton, the civil rights leader. Sharpton plans to visit St. Louis on Tuesday to meet with the Brown family.

“Policemen are to use deadly force to protect their lives,” he said. “If you’re looking at a kid
18 years old and you know he does not appear to be able to be concealing a weapon, then what is the life-threatening circumstances that would justify firing your weapon?”

Lowery reported from Ferguson, Mo. Berman reported from Washington.