Baltimore (CNN) Baltimore prosecutors on Wednesday dropped all charges against the three remaining officers facing trial in connection with Freddie Gray's death.

Gray, 25, died after sustaining a neck injury while in police custody in April 2015. Three of the six officers charged in the case had already been acquitted.

Gray's death became a symbol of the black community's mistrust of police and triggered days of protests and riots in Baltimore . The city became a focal point of the Black Lives Matter movement and the nationwide debate on excessive police force. Police said no extra officers will work the streets Wednesday night.

"Justice has been done," said Gene Ryan, president of the Baltimore Fraternal Order of Police, said after the charges were dropped.

But the city's top prosecutor didn't quite see it that way. Baltimore State's Attorney Marilyn Mosby said the decision was "agonizing," and she slammed the way police handled their investigation into the case.

Mosby: 'Inherent bias ... when police police themselves'

courthouse steps and More than a year ago, Mosby stood on her city'scourthouse steps and announced charges against the officers . "No one is above the law," she said as she read out charges that ranged from second-degree depraved-heart murder to manslaughter to second-degree assault.

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In a fiery address to reporters Wednesday, Mosby said she still believes Gray's death was a homicide. But now, she said, she realizes the criminal justice system needs "real, substantive reforms" to hold officers accountable.

"We could try this case 100 times, and cases just like it, and we would still end up with the same result."

Mosby said the case showed "an inherent bias that is a direct result of when police police themselves."

"There were individual police officers that were witnesses to the case, yet were part of the investigative team, interrogations that were conducted without asking the most poignant questions, lead detectives that were completely uncooperative and started a counter-investigation to disprove the state's case," she said, shouting into a microphone as she read her remarks.

Mosby, who comes from a long line of police officers, told reporters she isn't anti-police.

"We could try this case 100 times, and cases just like it, and we would still end up with the same result." Baltimore State's Attorney Marilyn Mosby

"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," she said.

Gray's stepfather, Richard Shipley, said Wednesday that he supported Mosby.

"We are pissed about the decision of the trials and the outcome of all the trials that have happened here in the city. We are very proud of the prosecutors who handled the case and did their best to their ability," Shipley said. "We stand behind Marilyn and her prosecuting team and my family's proud to have them represent us."

Police union: Prosecutor's comments 'outrageous'

Standing at a podium with the six officers who were charged, the police union chief called Mosby's comments "outrageous and uncalled for and simply untrue."

Evidence, he said, showed there was no wrongdoing.

Gene Ryan, center, flanked by attorneys and accused police officers.

"The state attorney simply could not accept the evidence that was presented," Ryan said. "She had her own agenda."

Investigators concluded Gray's death was an accident, said Ivan Bates, an attorney representing one of the officers.

"The thing that bothers me is this: We always attack the criminal justice system. We have to let the criminal justice system speak for itself. It gets it right," he said.

Baltimore Mayor Stephanie Rawlings-Blake told CNN that the prosecution's decision to drop charges made sense, given how the judge had ruled in the trials of the other three officers.

"I think (Mosby) made a wise decision, because the judge has found in the past that the cases were thin," she said.

Police Commissioner Kevin Davis, who took over for former Commissioner Anthony Batts in October, said 30 "ethical, experienced, and talented" detectives worked on the case and a local newspaper reporter was given access to the investigation.

"We knew the community would need a transparent assessment from an independent third party," the commissioner said.

Davis said the decision to drop the remaining cases was a wise and thoughtful one. He also said the relationship with Mosby's office was inherently strong and will remain so.

The commissioner's office said the officers are on administrative duty until a review by the Montgomery County Police Department is finished.

Van ride was key part of investigation

Gray died a week after police stopped him on a Baltimore street.

During his arrest, officers placed Gray in the back of a police van, which made several stops.

By the time the van arrived at the police station, Gray was unresponsive.

His neck was broken and compressed, prosecutors said in court , comparing the spinal injury to those suffered after a dive into a shallow pool.

What the officers faced

A pretrial hearing for Officer Garrett Miller had been set for Wednesday. Trials for Officers Alicia White and William Porter had been scheduled for the fall.

Baltimore Chief Deputy State's Attorney Michael Schatzow made the request to drop charges against them in court Wednesday.

Photos: Evolution of Black Lives Matter Black Lives Matter started with a hashtag. Now it is a rallying cry, a cause and a movement in the wake of the deaths of black men at the hands of police. The latest police shootings of Alton Sterling and Philando Castile have spurred a new round of protests across the country and worldwide. Hide Caption 1 of 18 Photos: Evolution of Black Lives Matter Some organizers say the acquittal of George Zimmerman in the death of Trayvon Martin in 2012 is where the movement began. Demonstrators wore hoodies and carried Skittles, the candy Martin had bought on the night he was killed. Hide Caption 2 of 18 Photos: Evolution of Black Lives Matter The shooting death of unarmed teen Michael Brown in August 2014 in Ferguson, Missouri, by an officer lit an existing fuse and protests engulfed the town. Hide Caption 3 of 18 Photos: Evolution of Black Lives Matter By the time Eric Garner died after being placed in a chokehold by a New York Police Department officer, support for Black Lives Matter had grown nationwide. Hide Caption 4 of 18 Photos: Evolution of Black Lives Matter Protests and clashes with police after the officer wasn't indicted in the death of Michael Brown in Ferguson led to another round of protests, with the rallying cry "No justice, no peace." Hide Caption 5 of 18 Photos: Evolution of Black Lives Matter Demands for change led to organized protests in major cities, including New York, Washington, Boston, San Francisco and Oakland, California, in December 2014. Hide Caption 6 of 18 Photos: Evolution of Black Lives Matter Activist Muhiyidin d'Baha took the call for action into a North Charleston, South Carolina, City Council after the killing of Walter Scott by a North Charleston police officer. Hide Caption 7 of 18 Photos: Evolution of Black Lives Matter The death of Freddie Gray in Baltimore led to frustrations that splintered into violence; a CVS Pharmacy was looted and burned during protests after his funeral. Hide Caption 8 of 18 Photos: Evolution of Black Lives Matter A battle waged against the Confederate flag as a symbol of hatred after Dylann Roof was accused of killing nine people in a South Carolina church in an attempt to spark a race war. Activist Brittany "Bree" Newsome took the battle flag off the flagpole at the Statehouse in Columbia, South Carolina. Hide Caption 9 of 18 Photos: Evolution of Black Lives Matter The political activism entered the 2016 campaign, with some parts of the movement deciding to interrupt presidential candidates to demand more be done. Hide Caption 10 of 18 Photos: Evolution of Black Lives Matter Black Lives Matter demonstrators made a point of protesting Democratic events to bring attention to their issues. The group had a tense meeting with Hillary Clinton in New Hampshire and released video of the conversation. Hide Caption 11 of 18 Photos: Evolution of Black Lives Matter The movement also worked its way into popular culture, sparking an episode of "Law & Order: Special Victims Unit," which took on a police officer killing an innocent unarmed black man. Hide Caption 12 of 18 Photos: Evolution of Black Lives Matter Black Lives Matter protesters continued to disrupt political events in an attempt to be heard, including this Hillary Clinton event in Atlanta. Hide Caption 13 of 18 Photos: Evolution of Black Lives Matter Racial tensions led to a weekslong protest movement at the University of Missouri campus that ousted both the university president and the school's chancellor. Hide Caption 14 of 18 Photos: Evolution of Black Lives Matter The movement was born out of frustration over the death of young black men. Jamar Clark's funeral in Minneapolis in November is an example of that continued unified response. Hide Caption 15 of 18 Photos: Evolution of Black Lives Matter Black Lives Matter demonstrators march in Cleveland on December 29, 2015, after a grand jury declined to indict Cleveland Police officer Timothy Loehmann for the fatal shooting of Tamir Rice on November 22, 2014. Hide Caption 16 of 18 Photos: Evolution of Black Lives Matter Sirica Bolling raises her fist as she walks down Jefferson Avenue during a Black Lives Matter protest in Newport News, Va., Sunday July 10, 2016, following the fatal shootings of Alton Sterling in Louisiana and Philando Castile in Minnesota. Hide Caption 17 of 18 Photos: Evolution of Black Lives Matter Demonstrations have popped up in cities around the world, including this one in London on July 10, 2016, following the most recent police shootings. Hide Caption 18 of 18

Three officers were previously acquitted in the case: Edward Nero , a bike officer involved in the initial police encounter with Gray; Caesar Goodson , who drove the van that transported Gray; and Lt. Brian Rice , the highest-ranking officer charged.

A retrial against Porter had been scheduled after a jury deadlocked in the case against him in December.

The prosecution's announcement Wednesday closed the criminal cases against the officers. But they still face administrative reviews and possible discipline.

Ryan told reporters Wednesday that most of the officers are already back at work.