Prosecutors detail timeline in first Freddie Gray trial

But defense attorney Gary Proctor said that the evidence will show Porter is innocent and that the department had just issued a new policy ordering officers to secure people in the van with seat belts.

"Mr. Gray's death is a tragedy," Proctor said, "but so is charging someone who did nothing to precipitate that."

Gray's spinal injury was similar to those suffered after a dive into a shallow pool, the prosecutor said. His neck was broken and compressed -- injuries that couldn't be caused by banging his head against a wall, he said.

Gray was unresponsive by the time the van arrived at the Western District police station. He died at a hospital on April 19, a week after his arrest.

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

The trial before eight women and four men is expected to offer answers to the lingering questions over how Gray was injured. There was "nothing wrong with his spine" when Gray entered the van, Schatzow said.

"When he is taken to the van, he stands," the prosecutor said. "He is standing by himself, bearing his weight."

At that point, Porter was working crowd control, Schatzow said. He was standing close by at the second stop when Gray was placed back into the van, facedown in a prone position, the prosecutor added.

By the fourth stop, Officer Caesar Goodson, the driver, was asking other officers for help, and Porter responded, the prosecutor said. At Goodson's request, Porter helped Gray onto a bench but didn't fasten his seat belt.

"There was no reason not to put him in a seat belt unless you didn't care," Schatzow said.

But Proctor offered jurors a reason: Porter didn't know about the new seat belt policy because it was in an email he hadn't seen.

"The facts are that he is an innocent man," Proctor said in his opening statement.

Porter, who is black, is the first of six Baltimore police officers to go on trial in connection with Gray's death. The jury that will judge him reflects the city's population, with eight blacks and four whites.

Franz Schneiderman, a potential juror who didn't make the final panel, said his fellow jury prospects felt the weight of responsibility and took their role seriously. In his closed-door session with the judge, Schneiderman said, he voiced his concerns about "police violence and unchecked police misconduct in certain communities in the city."

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

The trial 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. 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 Goodson's call for assistance. He later 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.

Court concluded Wednesday after the state presented its first witness, Alice Carson Johnson, an 18-year veteran of the police force and an instructor who taught Porter.

"If you recognize someone needs medical assistance, always call 911 or EMS," Johnson told the court, later adding, "A police officer is provided with the ability through appropriate training to make a determination if someone is in a medical emergency."

To the defense, Johnson acknowledged that someone speaking and saying they couldn't breathe was a sign they actually could breathe. 

The trial will resume at 9:30 a.m. ET Thursday.

The outcome of Porter's case could have a major impact on Goodson's trial, which is set to begin 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. Three of the officers are black, three white.

During two days of jury selection, the judge 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.

Members of Gray's family attended the opening statements, shielding themselves with an umbrella when they stepped out of the courthouse during the lunch break.

Porter and Gray 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 attorneys 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 to find an impartial jury 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.