Baltimore mayor Stephanie Rawlings-Blake (D) asked residents to respect the judicial process after a jury was unable to reach a verdict in the case of William G. Porter, one of six police officers charged in the case of Freddie Gray. (Reuters)

Jurors deliberated more than 16 hours over three days but still could not reach a verdict in the trial of the first officer to face prosecution in Freddie Gray’s death, forcing an already-weary Baltimore to continue waiting for any resolution in a case that has strained the city for months.

Hours after Baltimore Circuit Court Judge Barry G. Williams declared a mistrial on Wednesday, court officials announced that he would meet with attorneys Thursday to determine a new trial date.

Perhaps no outcome could have better represented the mood here, where residents are deeply divided about what led to and who should be held responsible for the fatal neck injury Gray suffered in the back of a police van in April. Riots ripped through West Baltimore on the day of his funeral as the incident became a defining moment in the national movement protesting the treatment of African Americans by law enforcement.

The jury — made up of what appeared to be seven black and five white members — failed to reach unanimity on a single charge after hearing two weeks of passionate legal arguments and contradictory witness testimony, leaving prosecutors to try Officer William G. Porter a second time. He has pleaded not guilty to involuntary manslaughter, second-degree assault, misconduct in office and reckless endangerment.

Outraged by the news, more than 100 protesters confronted deputies in downtown Baltimore on Wednesday night. But Gray’s family — which in September agreed to a $6.4 million wrongful death settlement from the city — pleaded with residents to stay patient and let the judicial process work.

“Once again, we are asking the public to remain calm,” the family said in a statement. “If we are calm, you should be calm too.”

The mistrial, legal experts said, may upend prosecutors’ plans to quickly try the five other officers who have been charged in the case.

The van’s driver, Officer Caesar R. Goodson Jr., is scheduled to go on trial Jan. 6, when he will face the case’s most serious charge: depraved-heart second-degree murder.

“Officer Porter shifted blame to the van driver, Officer Goodson, in his testimony,” said Warren Alperstein, a defense lawyer and former Baltimore prosecutor. “The state had hoped to use Officer Porter’s testimony against Goodson at his trial. With a case possibly pending against Porter, he could invoke his Fifth Amendment right not to testify.”

Attorneys are probably desperate to learn whether the jury, which has been guaranteed anonymity by the judge, was leaning in either direction.

The fact that they were deadlocked on all charges — and couldn’t even convict Porter of a relatively minor misconduct count — is probably a good sign for the defense, said David Felsen, a Maryland defense lawyer. But he cautioned that their indecision is difficult to interpret without talking to them.

“Maybe,” he said, “that’s just one hold-out juror who didn’t want to convict a police officer of anything.”

After the trial’s end, Baltimore State’s Attorney Marilyn J. Mosby, who drew national attention when she announced the charges in May, hugged the prosecutors and quickly exited the courtroom, telling reporters with a smile that a court-issued gag order meant she could say nothing.

How the broader community will react in the days to come is hard to predict. Baltimoreans had long anticipated and, in some cases, dreaded a verdict. Many in Gray’s West Baltimore neighborhood — known for its poverty, violence and steadfast distrust of police — feared that if several or even just one officer were acquitted, more upheaval would inevitably follow.

In a city that is also contending this year with a record-high murder rate, government officials have quietly braced for a backlash. The police department banned officers from taking leave, area schools warned students not to participate in civil unrest and politicians begged residents to remain peaceful.

The corner of Pennsylvania and North avenues — where a CVS was looted eight months ago on live TV — remained largely quiet Wednesday night.

Tessa Hill-Aston, president of the Baltimore City NAACP, said she expected Porter to be convicted of at least some of the lesser charges.

“I’m frustrated and disappointed,” she said. “We know this much: His neck was broken. We know Freddie is dead. We also know somebody needs to pay for it.”

Gray, 25, was arrested April 12 after he spotted officers in his neighborhood and ran — reason enough for officers patrolling Sandtown-Winchester to pursue. After he was dragged to the police van, prosecutors said, his spine was nearly severed when he fell in the back of the wagon; his hands and feet were shackled but he was not restrained by a seat belt. It remains unclear precisely how Gray was injured, but medical experts on both sides of the case compared his injury to those sustained when someone dives headfirst into too-shallow water.

Attorneys for the defense and prosecution called more than 20 witnesses, presented about 100 pieces of evidence and made hours of fervent arguments in their competing efforts to explain Porter’s actions that day.

Prosecutors alleged that Porter, 26, disregarded his duty by not strapping Gray into the van while also failing to get him medical help when he asked for it and, at one point, claimed he couldn’t breathe. When the wagon reached a station, Gray was found unresponsive and died in a hospital a week later.

“He abused his power. He failed in his responsibility. Hold him responsible,” prosecutor Janice Bledsoe had told jurors in her closing argument, at one point calling the police van in which Gray was injured “his casket on wheels.”

Defense attorneys presented a starkly different version of events, arguing that Porter was a conscientious officer who acted reasonably given what he knew at the time. They asserted that Gray showed no obvious signs of injury and did not articulate any specific problems. Despite that, his attorneys said, Porter twice asked Gray whether he needed a medic and told colleagues that Gray should go to the hospital. Several officers testified that arrestees were rarely, if ever, buckled into police vans.

“You’re making a legal decision — not a moral, not a philosophical — a legal decision,” defense attorney Joseph Murtha told jurors Monday. “You set aside the sympathies, you set aside the passions, you look at the cold, hard facts that aren’t there in this case.”

The trial — which the defense repeatedly insisted should be relocated because of the immense publicity — was rife with dramatic episodes, beginning at jury selection when demonstrators’ chants filtered into the marbled courtroom: “We won’t stop until killer cops are in cellblocks.”

Later, after prosecutors played shaky cellphone video of Gray’s arrest, his mother, Gloria Darden, began to sob, prompting Williams to pause the proceedings. Wrapped in the arms of another woman, she was escorted outside.

But no moment was more anticipated than when Porter took the stand, calmly addressing the jury for four hours.

Porter described growing up in the same neighborhood as Gray, someone the officer said he had a “mutual respect” for but who he said feigned injury to avoid arrest.

“It was a very traumatic thing for me,” he said of Gray’s death. “Any loss of life, I’m sorry to see that.”

His testimony intensified during cross-examination when prosecutor Michael Schatzow suggested that he was involved in a cover-up driven by officers’ unwillingness to “snitch” on one another.

“Is that culture in the Baltimore Police Department?” Schatzow asked.

“Absolutely not,” Porter replied. “I’m offended you would even say something like that.”

In Sandtown, at the spot where police arrested Gray, there’s a small mural in his memory painted on a corner of a red-brick apartment building. Beneath it on Wednesday night were bunches of wilted flowers, a few soiled stuffed animals, an old sneaker, a half-empty bottle of 1800 tequila.

An occasional passerby appeared in the yellowish glare of the security spotlights on the buildings, but none stopped to contemplate the mural.

Here in the dark of evening, a few hours after the mistrial had been declared and as faraway protesters dispersed, Freddie Gray’s old neighborhood remained quiet in the cold.

DeNeen L. Brown, Ovetta Wiggins, Josh Hicks, Keith L. Alexander, Dan Morse, Rachel Weiner and Paul Duggan contributed to this report.

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