Wednesday marks the third day of deliberations in the case of William Porter. He's one of six officers charged in Gray's death.
On Tuesday afternoon, jurors sent the judge a note saying they were deadlocked. He told them to keep working.
Porter is charged with manslaughter, assault, reckless endangerment and misconduct in office.
Prosecutors say Porter is partly responsible for failing to buckle Gray into a seatbelt and for not calling an ambulance when Gray indicated he was in distress. Porter told jurors that he didn't think Gray was injured and that it was the van driver's responsibility to fasten Gray's seat belt.
Gray died April 19, a week after his neck was broken in the back of a police van with his wrists and ankles shackled. Porter is charged with manslaughter, assault, reckless endangerment and misconduct. He faces up to 25 years in prison.
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 are being stationed around the city ahead of any verdict from the jury in the trial. 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.
Prosecutors described Officer William Porter as indifferent to Gray's safety, repeatedly denying him medical care in the police wagon where his neck was broken after he was left handcuffed and shackled but unbuckled on the floor of the van, vulnerable to a serious injury if the brakes were slammed.
The wagon "became his casket on wheels" after Porter failed to belt him to the bench or call for a medic after he was injured, prosecutor Janice Bledsoe said in her closing arguments. Gray was arrested about seven city blocks from the station, and yet police stopped the van repeatedly and the trip became a 45-minute journey.
"With great power comes great responsibility," Bledsoe said. "Porter had the opportunity on four or five occasions to wield his power to save Freddie Gray. He abused his power. He failed his responsibility."
Defense attorney Joseph Murtha countered that nothing more than conjecture and speculation implicates his client.
Gray's death was a "horrific tragedy," Murtha said, but "there is literally no evidence" that Porter caused it.
"The absence of real evidence raises much more than reasonable doubt," Murtha told jurors. "This case is based on rush to judgment and fear. What's an acronym for fear? False evidence appears real."