Nero has pleaded not guilty to the charges.
Gray, 25, suffered severe spinal cord injuries while in the back of a Baltimore police van, prosecutors say. He died a week later.
Williams is expected to hand down his ruling at 10:30 a.m.
The charges
Second-degree assault carries a penalty of up to 10 years in prison. Reckless endangerment carries a penalty of up to five years in prison. Misconduct in office does not carry a set term limit. All charges are misdemeanors.
The defendant
Officer Edward Nero, a former New Jersey volunteer firefighter who joined the Baltimore Police Department in 2012, is one of three officers who were on bike patrol when they chased and arrested Gray. He is suspended with pay from the police force, per policy.
What has happened thus far?
The trial lasted six days, with the prosecution calling 14 witnesses and the defense calling seven before closing statements Thursday. Prosecutors are alleging that Gray's arrest was an assault because it did not meet the standards of a legal detention. Legal analysts have called the theory unusual. The defense has sought to minimize Nero's role in the arrest, saying for example he had touched Gray only once. The defense has argued that the officer followed his training.
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