The jury in the manslaughter trial of a Baltimore police officer charged in the death of Freddie Gray will resume deliberations Wednesday morning after telling the judge Tuesday they were deadlocked.

The jury sent a note to Baltimore Circuit Judge Barry Williams on Tuesday afternoon after about nine total hours of deliberations over two days in the trial of Officer William Porter. He is the first of six officers to stand trial on charges stemming from Gray's death in April.

The jury has also sent out notes asking for water, highlighters, sticky notes and paper. They also requested the clerk's list of exhibits in evidence, which the judge denied.

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Williams ordered the panel to continue deliberating, which they did until early evening. Deliberations will continue at 9 a.m. Wednesday.

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."