(CNN) — A jury is expected to be chosen Wednesday in the trial of a Baltimore Police Department officer charged in the death of Freddie Gray.

Officer William G. Porter Jr. is the first of six city police officers to go on trial in the closely watched case involving Gray, a 25-year-old black detainee who died in police custody.

Protests followed Gray’s death and erupted on April 27 — the afternoon of his funeral — in the worst rioting Baltimore had seen in nearly half a century.

The trial is expected to shed light on how Gray suffered a severe spinal injury after his arrest, some of which was captured on bystander video. After being shackled, he was placed in the back of a police van and driven through the city streets.

At some point during the van ride, which lasted more than 40 minutes, Gray requested medical assistance. He was unresponsive by the time he arrived at the Western District police station and died at a hospital a week later, on April 19.

Although it won’t be televised or tweeted live, the trial of Porter, 26, will be closely followed over the next two weeks. Judge Barry Williams has said he expects a verdict by December 17.

The testimony comes at a time of increased national conversation over the deaths of young blacks at the hands of police; the Baltimore police trials are considered by some to be an acid test for the criminal justice system.

Porter has pleaded not guilty to charges of involuntary manslaughter, negligent assault, misconduct in office and reckless endangerment. He is accused of ignoring Gray’s pleas for help and failing to properly secure him in the back of the police van. In essence, Porter is going on trial for what he allegedly failed to do — not for anything he did.

Porter, who joined the city’s police force in 2012, answered a call for assistance from the driver of the police van, Officer Caesar Goodson. The driver asked him to check on Gray. Porter told department investigators that Gray responded “yes” when asked if he needed a medic and complained he couldn’t breathe.

Porter also said he helped lift Gray onto a bench inside the van, but he did not closely assess the prisoner’s condition or summon medics. The Baltimore Sun, citing an anonymous source close to the department’s internal investigation, reported that Porter questioned whether Gray was faking.

The outcome of Porter’s case could have a major impact on Goodson’s trial, which is set to begin on January 6.

Goodson, the lead defendant in the May 1 indictment, is charged with the most serious offense — second-degree murder with a depraved heart. Trials for the other officers — Alicia White, Garrett Miller, Edward Miller and Brian Rice — will follow later in 2016. The six are being tried separately, one after another.

During two days of jury selection, Williams asked the potential panelists a series of questions about what they knew about the case. He also delved into their experiences with the criminal justice system and probed their attitudes about race and police.

All members of the racially diverse pool of jurors indicated they knew about Gray, and all but one was aware of the city’s decision to pay Gray’s family $6.4 million to settle legal claims over his death.

Porter and Gray, both black, grew up in the same impoverished West Baltimore neighborhood. Through a show of hands, all but two of the approximately 150 jury prospects indicated they did not have strong feelings about the race of the two men. But about a quarter of them acknowledged strong feelings about police misconduct.

Porter’s lawyers have said in court documents that he intends to testify in his own defense. And the defense intends to call Donta Allen, another detainee who was in the van at the same time as Gray. Also expected is expert forensic testimony about Gray’s injuries and how he might have gotten them.

Porter’s attorneys have repeatedly asked the judge to move the trial out of Baltimore, arguing that it would be impossible for him find an impartial jury just seven months after the city erupted in violence over Gray’s death. Baltimore was so torn by rioting that the mayor imposed a curfew and Maryland’s governor called in the National Guard to help restore order.

The chants of protesters on the streets below could be heard in the courtroom on the first day of jury selection. But by the second day, a cold, steady rain brought silence.

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