(Updates with quotes from parents, adds details of FBI probe)
By Jason McLure
FERGUSON, Mo., Aug 11 (Reuters) - The mother of a black teenager from suburban St. Louis who was shot to death by police over the weekend begged for non-violence on Monday in the wake of riots, as the FBI opened a probe into the racially charged case.
Michael Brown, 18, was shot to death in the mostly black suburb of Ferguson, Missouri on Saturday afternoon after what police said was a struggle with a gun in a police car.
A witness in the case told local media that Brown had raised his arms to police to show that he was unarmed before being killed.
"He just graduated and was on his way to college," said Brown's mother, Lesley McSpadden, speaking through tears at a news conference. She said her first-born son's first day back at school would have been Monday.
"We can't even celebrate," she said.
Brown's family has hired Benjamin Crump, the attorney who represented the family of Trayvon Martin, a black teenager who was shot to death by a community watch volunteer in 2012.
The FBI opened a concurrent federal inquiry into the case intended to supplement the main investigation by St. Louis County police, according to the U.S. Department of Justice.
It was not immediately clear from police why Brown was in the police car. At least one shot was fired during the struggle, and then the officer fired more shots before leaving the car, police said.
OFFICER NOT IDENTIFIED
The officer, who was not identified, is a six-year veteran and has been put on administrative leave, police said. The officer's race has not been disclosed.
Dorian Johnson told television station KMOV that he and Brown had been walking when an officer confronted them, drew a weapon and shot. Johnson said that Brown put his hands in the air and started to get down, but the officer kept shooting.
Ferguson Police Chief Tom Jackson said there was plenty of physical evidence and eyewitness testimony. "I really believe we can get to the truth of what happened here," he said.
Demonstrations to call for justice for Brown turned violent Sunday night, with crowds breaking the windows of cars and stores, setting a building on fire and looting shops. At least two dozen businesses were damaged, 32 people were arrested, and two police officers were injured.
Hundreds of demonstrators gathered at the town's police station on Monday to demand murder charges against the officer responsible for the shooting. Police arrested up to 15 people on Monday during the mostly peaceful demonstration in which protesters put their hands in the air as if surrendering and chanted "Stop the killer cops."
Brown's mother said her son had been planning to study heating and air conditioning repair at a technical college.
Michael Brown, Sr., the teen's father, told reporters his son was "silly" and "could make you laugh."
"We need justice for our son," he said.
Three of the Ferguson Police Department's 53 members are black, Jackson said. About two-thirds of Ferguson's population of about 21,000 are black, according to U.S. Census figures.
Ferguson's median household income is $37,517, less than the Missouri average of $47,333.
Most of the communities around Ferguson have gone from white to mostly black in the last 40 years, said Terry Jones, political science professor at University of Missouri-St. Louis.
"There's a long history of racial injustice," said Jones. "Slowly and not so surely, the St. Louis metropolitan area has been trying to figure out a way forward. As the Michael Brown shooting indicates, there are often setbacks." (Additional reporting by Mary Wisniewski in Chicago; Editing by Edith Honan and Eric Walsh)