Last Updated Dec 16, 2015 10:22 PM EST
BALTIMORE - A Baltimore jury declared a mistrial in the case of the first police officer to stand trial over the death of Freddie Gray, whose injury in police custody sparked weeks of protests and fueled the nation's scrutiny of how police treat black suspects.
Officer William Porter's trial was the first test of prosecutors' case against six officers in a city struggling to rein in violent crime.
The case hinged not on what Porter did, but what prosecutors said he didn't do.
He was accused of failing to get medical help for a critically wounded Gray and was charged with manslaughter, assault, misconduct in office and reckless endangerment. The charges carried maximum prison terms totaling 25 years.
It was not immediately clear whether Porter would be tried again. Prosecutors haven't officially declared their intentions yet, but they will meet privately Thursday with the judge and defense attorneys to talk about dates for a possible retrial.
Baltimore Mayor Stephanie Rawlings-Blake immediately appealed for calm after the verdict.
"As a unified city, we must respect the outcome of the judicial process," Rawlings-Blake said.
She said in the case of any disturbance in the city, authorities were prepared to respond.
"We will protect our residents, our neighborhoods, our businesses and the safety of our first responders," Rawlings-Blake said.
"We will not, we cannot be defined by the unrest of the spring," she added.
Police Commissioner Kevin Davis said protesters have "a friend" in the department, but people who commit crimes and hurt people lose their right to call themselves demonstrators.
Billy Murphy, an attorney representing Gray's mother and stepfather, said he has every confidence Porter will be convicted if he is tried a second time.
Murphy said hung juries are "part of how the system works." According to Murphy, Gray's family is not angry and that they want people to remain calm, understand what happened and keep their emotions in check.
Rep. Elijah Cummings, D-Maryland, issued a statement after the mistrial, acknowledging "many may be disappointed by today's outcome. Each of us will continue to struggle with the very raw, very real emotions the death of Mr. Freddie Gray invokes."
Cummings echoed the calls for demonstrators to remain peaceful.
"With the eyes of the world on Baltimore City, we must ensure that any protests that take place are peaceful, and we must ensure that the process of healing our community continues," Cummings said. "We must continue to channel our emotions into strong, positive change, so that, as a city, we truly see our young men of color before it is too late.
"This is the road to more equal justice in our community," he concluded.
"While we respect the legal process and still await justice, the death of Freddie Gray and other tragedies continue to point to the need for systemic reform both within the municipal police departments and statewide," the NAACP said in a statement. "We call on the community to continue the protests while using all of the available nonviolent means to seek justice for a violent death."
After court adjourned, Porter conferred solemnly with defense attorney Joseph Murtha and walked from the courtroom. A female supporter joined Porter on a marble bench in a corner of the hallway. Courthouse deputies blocked reporters from approaching them.
Murtha declined comment, citing a judicial gag order. Baltimore City State's Attorney Marilyn Mosby, who brought charges against six officers in the arrest and death of Gray, also declined comment.
The jury said yesterday it was deadlocked in the case of Porter, but Baltimore Circuit Judge Barry Williams sent them back to talk it over more.
The announcement of the hung jury came Wednesday afternoon, after the city had spent days worrying about the repeat of civil unrest following Gray's death.
"It is clear you will not come to a unanimous agreement on any of the four charges," Williams told the jurors before declaring a mistrial. Before dismissing them, he said, "You have clearly been diligent."
CBS Baltimore reports Williams previously decided the jury would not be sequestered, but would remain anonymous for the trial. It took two days to find the 12 jurors on the case -- 5 black women, 3 black men, 3 white women, 1 white man and alternates 3 white men, 1 black man.
As the decision was announced a handful of protesters gathered outside the courthouse, some chanting "no justice, no peace."
Throughout the evening, small crowds protested along streets lined with police officers. The situation was quiet at the intersection where the worst rioting happened in April, when parts of West Baltimore were set on fire.
At least two activists were arrested in the immediate aftermath of the mistrial. Television footage showed Baltimore sheriff's deputies taking Kwame Rose into custody, putting his arms behind his back and marching him into the courthouse.
Earlier, he told The Associated Press: "This is an injustice, and we are going to fight for justice until it becomes a reality in our lives. A mistrial means that the prosecution did not do their jobs good enough."
Erika Alston is a West Baltimore community leader and founding director of Kids Safe Zone, an organization formed after the April riots following the death of Gray.
She said the mistrial left her "kind of numb" and she didn't think after closing arguments that the jury would reach a guilty verdict.
Duane "Shorty" Davis, a local activist, said he thought the state's attorney put on a "weak case."
"I think the state's attorney went in there with the intention of losing," Davis said.
Police said an officer-involved shooting in southwest Baltimore Wednesday night was not related to the protests. A 17-year-old armed suspect was wounded in the leg and taken to a hospital with non-life-threatening injuries.
Gray died April 19, a week after his neck was broken in the back of a police van with his wrists and ankles shackled.
Gray's death set of riots around Baltimore, and highlighted a police department that many citizens say is abusive. As a result, many local officials feel the outcome of Porter's trial could touch off unrest again.
CBS affiliate WJZ reported defense attorneys asked for a mistrial and change of venue Tuesday morning because of a letter sent by Baltimore City schools. In it, the city schools CEO said he was very concerned about possible city unrest. Defense attorneys said some jurors may have gotten it because they are parents and it could influence their decision. The judge denied the motions, saying he wasn't concerned about that.
Armored vehicles and police were stationed around the city ahead of any verdict. Baltimore County Public School spokesman Mychael Dickerson said Tuesday that the school system is postponing, and in some cases canceling, field trips and events in Baltimore city through Friday. The county surrounds most of the city and extends north to Maryland's border with Pennsylvania.