It's not getting any easier.
But on Wednesday Mosby said she had no choice but to drop the charges -- ending a 15-month legal saga that strained relations between her office and the city's police department.
'Dismal likelihood of conviction'
Still, Mosby struck a defiant tone. Standing at the intersection where police arrested Gray in April 2015 she railed against police officers whom she accused of kneecapping her office's investigation.
Police investigating police is "problematic," she said, citing "the obvious bias consistently exemplified" by some officers throughout the case. Officers who were witnesses were placed on the investigation team, lead detectives were uncooperative, the department launched a "counter-investigation" to disprove her case and officers created notes after the case was launched and gave them to the defense months before they were provided to the state, she alleged.
Baltimore Fraternal Order of Police President Gene Ryan called Mosby's accusations "outrageous" and "simply not true." Ivan Bates, an attorney for Sgt. Alicia White -- one of the six accused officers -- appeared at police union headquarters with his client and the other five officers and said it was Mosby's office that had denied the Gray family justice.
CNN legal analyst Paul Callan, a former prosecutor, said Mosby's passionate speech that suggested police collusion and tampering with evidence, was "the most inflammatory statement I have ever seen a prosecutor deliver."
'Not an indictment' of all police
Mosby, 35, comes from a long line of police officers, including her late grandfather, four uncles and her mother. Her grandfather, she noted, was a founding member of the first African-American police organization in Massachusetts.
While announcing charges, Mosby said she was not anti-police.
"To the rank-and-file officers of the Baltimore City Police Department, please know that the accusations of these six officers are not an indictment on the entire force," she said at the time. She reiterated that sentiment during Wednesday's remarks.
"For those that believe that I'm anti-police, it's simply not the case. I'm anti-police brutality. And I need not remind you that the only loss -- and the greatest loss -- in all of this was that of Freddie Gray's life," Mosby told reporters Wednesday.
Gray died at hospital April 19, 2015, from a fatal spinal cord injury, one week after he was taken into custody. Prosecutors argued the 25-year-old suffered the injury while being transported "handcuffed, shackled by his feet and unrestrained" inside a police van. It is against police policy to transport a prisoner without proper restraints such as a seat belt.
Gray's mysterious death turned the largely black city near the nation's capital into a tinderbox. Mostly peaceful demonstrations erupted in pockets of looting and rioting in the hours after Gray's funeral. A citywide curfew was put into effect, and National Guard troops joined Baltimore police in an attempt to maintain order.
As police handed their investigative files
over to the state attorney's officer a day earlier than planned, supporters of the former insurance company lawyer expressed confidence in Mosby's ability to handle the volatile case.
'We have much more confidence in her'
"We're enthusiastic about the new prosecutor," said William "Billy" Murphy Jr., a former Baltimore judge who is lead attorney for Gray's family. "She comes to the office with a belief in the integrity of these kinds of investigations. We have much more confidence in her than we have in the police because there's never been any level of confidence, nor should there be, in the police investigating themselves."
Mosby said last year that while police regularly briefed her office on their findings, her team would conduct its own independent probe into the death.
"We ask for the public to remain patient and peaceful and to trust the process of the justice system," she said.
Mosby is married to Baltimore City Councilman Nick Mosby, who represents areas of West Baltimore where riots erupted in April 2015. The Mosbys have two young daughters.
"She's a strong woman," Nick Mosby told CNN at the time. "She was built for this. ... I was at church service the other day and they were talking about being at the right place with the right person at the right time. I know her heart has always been convicted to ensure that justice will be served fairly and equally across the board."
Cousin's death brought exposure to criminal justice system
During her campaign against Gregg Bernstein in 2014, Mosby spoke about the broad-daylight shooting death of her 17-year-old cousin on her front doorstep.
"I learned very early on that the criminal justice system isn't just the police, the judges and the state's attorney," she said. "It's much more than that. I believe that we are the justice system. We, the members of the community, are the justice system because we are the victims of crimes."
Mosby said her cousin's 1994 murder was her introduction to the criminal justice system.
"Having to go to court and deal with prosecutors," she said. "Having to go to court and see my neighbor who had the courage and audacity to cooperate with the police ... to testify in court and the way the district attorney's office treated my family is something that inspired me."
Mosby, who grew up in Boston, is the youngest chief prosecutor of any major American city, according to the state's attorney's website.
At age 6, Mosby was accepted into a school desegregation program in Massachusetts. She later participated in a study of the civil rights movement.
"After having that awesome experience I knew I wanted to be an attorney," she said during her campaign.
A. Dwight Pettit, a civil rights attorney and Mosby supporter, said at the time charges were filed against the six officers that he felt Mosby would "deliver on doing it right, and getting it right. I'm confident in that."
"She's very dedicated and part of what she campaigned on was bringing integrity to the office, and so I believe that she will move in a methodical way," he said. "And I think that she will follow where the evidence leads. I do not think she will follow just public opinion."
Prosecutor said it's time to rebuild trust
When she was sworn in as chief prosecutor in January 2015, Mosby brought up the lack of trust between the community and police.
"Our time to repair that trust, to come together collectively as a community to start to break down the barriers to progress in our communities is now," she said.
Mosby added, "As a black woman who understands just how much the criminal justice system disproportionately affects communities of color, I will seek justice on your behalf."
Mosby is African-American, as are Mayor Stephanie Rawlings-Blake and other leading Baltimore officials. About 63% of Baltimore's population is black, but the city faces stunning disparities
between black and white residents when it comes to income, employment, poverty, housing, incarceration and overall health.