Marilyn Mosby, 35, grew up in Boston and from age 6 she knew that she wanted a career in law.

BALTIMORE — Baltimore State’s Attorney Marilyn Mosby walked down the steps of the Baltimore War Memorial Building on Friday and made a stunning announcement: The officers involved in Freddie Gray’s arrest would be charged.

Almost as stunning: Mosby is just 35 and has been on the job for less than four months.

The African-American lawyer ousted a white incumbent, Gregg Bernstein, in the Democratic primary by promising to hold police accountable.

She echoed that sentiment Friday as she talked about Gray’s relatives. “I assured the family,” she said, “that no one was above the law.”

Gray, 25, died April 19, a week after suffering a severe spine injury while in police custody. His death has touched off days of unrest in Baltimore.

While many in Baltimore celebrated the charges, some in the law enforcement community questioned them. Around the same time that Mosby made her bold announcement, the police union asked that she appoint a special prosecutor to determine whether charges should be filed.

BOSTON POLICE FAMILY

Former Baltimore Mayor Kurt Schmoke, who served on Mosby’s transition team, dismissed the criticism.

“The call for her to step aside is misguided,” said Schmoke, who was Baltimore’s first elected black mayor and is now president of the University of Baltimore. “There is no basis in fact to question her integrity or independence in this matter.”

Mosby, who has two young daughters, comes from a family steeped in law enforcement experience. Her mother, her grandfather and two of her uncles were Boston police officers.

“She always wanted to be an attorney and work for the community,” said her mother, Linda Thompson, 52. “The world’s her stage right now, and she’s shining like a star.”

Mosby grew up in Boston and knew from age 6 that she wanted a career in the law, Thompson said.

After little Marilyn badly cut her knee in a yard littered with broken glass, her mother sued the landlord. On their day in court, Marilyn was twirling in the middle of the room before the proceedings began, her mother said.

The judge, Thompson recalled, looked down at her.

“Hi, little girl,” the judge said. “What do you want to be when you grow up?”

Marilyn didn’t hesitate: “A judge.”

“Never wavered,” Thompson said. “Never, ever, ever.”

‘NO JUSTICE, NO PEACE’

Mosby met her husband while they were students at Tuskegee University in Alabama. She later attended Boston College Law School. After clerking at U.S. attorney’s offices in Boston and Washington, she joined the Baltimore State’s Attorney’s Office in 2005 and moved up the ranks before leaving to work for an insurance company.

Her opponent, Bernstein, had raised three times as much money for his campaign. But after she defeated him in June’s Democratic primary, Mosby faced only write-in opposition in the general election.

Gray’s death represents her biggest test in office.

On Friday, she was composed as she outlined one of the most detailed accounts of what happened the night Gray was arrested. Helicopters circled overhead as she spoke. People in the crowd leaned forward and strained to hear her above the traffic on Gay Street.

She urged protesters to “channel your energy peacefully” and assured them that she had heard their calls of “No justice, no peace.”

She also addressed the city’s police force, noting that her family had worn badges.

“To the rank and file of the Baltimore City Police: These accusations are not an indictment of the entire force,” she said, praising their hard work and dedication. “Thank you for your courage.”

ANOTHER HIGH-PROFILE CASE

It wasn’t the first time that Mosby had moved quickly to file charges in a high-profile case. The day after she was inaugurated, on Jan. 8, she brought manslaughter charges against a top Episcopal bishop accused of hitting a bicyclist while driving under the influence of alcohol and texting while driving.

Heather Elizabeth Cook, 58, was driving her 2001 Subaru on Roland Avenue in Baltimore on the afternoon of Dec. 27 when she veered into the bike lane where Thomas Palermo, a father of two, was riding.

Mosby moved the case from district court, where it was a traffic matter, to circuit court, where the bishop was charged with manslaughter.

In the Gray case, the announcement of the charges against the six officers restores faith in the criminal justice system in Baltimore, said Maryland State Delegate Jill Carter, who represents Maryland’s 41st legislative district of Baltimore in the Maryland House of Delegates.

Carter, a defense attorney, said she was impressed that Mosby came out so forcefully.

“It was a stronger and more transparent announcement than any of her predecessors,” Carter said. “She set a new precedent.”