The announcement was made on Wednesday afternoon following 14 hours of deliberations. The jury failed to reach a verdict on all charges against Porter, including second-degree assault, involuntary manslaughter, reckless endangerment, and misconduct in the line of duty.He pleaded not guilty to all charges.
"It is clear we have come to a point that we will not reach a unanimous agreement on any of the four charges," reads a note from the jury, according to the Guardian.
The judge has also reportedly issued a gag order on the jury.
It is unclear what effect this outcome will have on the trials of the other five officers allegedly involved in the Gray's death. Porter will likely be retried.
Tensions were high outside the courthouse, with heated confrontations between demonstrators and police. Authorities are preparing for potential unrest, as Freddie Gray's death led to mass riots in Baltimore earlier this year. Many viewed Porter's trial as a sign of hope that police officers could be held accountable in instances of brutality.
Baltimore Mayor Stephanie Rawlings-Blake has released a statement calling for calm.
"In the coming days, if some choose to demonstrate peacefully to express their opinion, that is their constitutional right," the statement reads. "In the case of any disturbance in the city, we are prepared to respond. We will protect our neighborhoods, our businesses and the people of our city."
"With great power comes great responsibility. Voltaire said that – and Spiderman," Prosecutor Janice Bledsoe told jurors during Monday's closing arguments, according to the Washington Post. "He abused his power. He failed in his responsibility. Hold him responsible."
Porter’s defense called Gray’s death a "horrific tragedy," but not one for which Porter should be held responsible.
— Sarah Jacobs (@SarahJacobsWNEW) December 16, 2015
"The absence of real evidence raises much more than a reasonable doubt," attorney Joseph Murtha argued. "You’re making a legal decision, not a moral, not a philosophical; a legal decision. You set aside the sympathies, you set aside the passions, you look at the cold hard facts that aren’t there in this case," he pleaded.
Porter is one of six officers charged in the death of Freddie Gray last April. The 25-year-old Gray was arrested by Baltimore police and placed in the back of a van for transport. While his feet and hands were shackled, authorities broke protocol by not attaching Gray’s seatbelt, a decision which prosecutors allege led to his death.
A medical examiner determined that Gray suffered a severe neck injury while inside the transport vehicle.
During one of the van’s stops, Porter allegedly failed to request medical assistance even after Gray told the officer that he couldn’t breathe.
"Officer Porter knew how serious the injury was," Bledsoe argued.
Freddie Gray’s death led to widespread rioting in Baltimore. Police are preparing for additional violence in the wake of the Porter verdict.
"The community has an expectation for us to be prepared for a variety of scenarios," police commissioner Kevin Davis said in a press release, adding that all scheduled police leave for the week has been canceled "in order to ensure adequate staffing."
During Porter’s trial, a handful of protesters gathered peacefully outside of the courthouse.