Baltimore (CNN) The driver of the transport van in which prosecutors say Freddie Gray suffered a fatal spinal injury took him on a "rough ride," said the chief deputy state's attorney.

Officer Caesar Goodson, who faces the most serious charges in a controversial case that sparked days of unrest in Baltimore, ran a stop sign and veered into another lane of traffic while making a turn because of the speed he was traveling, prosecutor Michael Schatzow said during opening statements Thursday.

Goodson bears the "ultimate responsibility" for the fate of his prisoner, Schatzow said. Gray was not wearing a seat belt when he was being transported after an arrest in April 2015.

But Andrew Graham, Goodson's attorney, told the court his client was a good officer who followed department procedure.

Evidence of a rough ride by Goodson does not exist, Graham argued. Gray's injuries were caused in part by his own agitation and thrashing around in the van, the attorney said.

"Freddie Gray's death was a tragedy," Graham said, adding that convicting a good cop out of what he calls a desire to assign blame makes a tragic situation worse.

A "rough ride" is a reputed police tactic reserved for particularly resistant suspects.

Goodson is the third of six officers tried in the case.

On Monday, the officer elected for a bench trial, meaning his fate will be decided by the same judge who acquitted a Baltimore officer last month on charges related to Gray's controversial death last year.

Judge Barry Williams on May 23 acquitted Officer Edward Nero, one of three bicycle officers involved in the initial police encounter with Gray.

Before opening arguments, Williams declined a defense request to dismiss the charges against Goodson, but he blasted the state for not disclosing a meeting last year with a man who was being held in the van at the same time as Gray. In the meeting with Dante Allen, prosecutors said no notes were taken.

Williams suggested that Schatzow did not understand the rules surrounding discovery and asked the state to take inventory of pending cases and immediately disclose any information they may be withholding.

"I'm not saying you did anything nefarious," Williams said. "I'm saying that you don't understand what exculpatory means."

Goodson faces charges alleging second-degree depraved-heart murder, second-degree assault, misconduct in office, involuntary manslaughter, manslaughter by vehicles (gross negligence), manslaughter by vehicle (criminal negligence) and reckless endangerment.

CNN legal analyst Andrew Alperstein said a bench trial could help Goodson. Williams has demonstrated an ability to put aside the emotions that surrounded Gray's death, he said.

Gray died after suffering a spinal injury during an arrest in April 2015.

Seat belt use key part of testimony

In opening arguments, Schatzow said Goodson was "no rookie, no inexperienced officer." Goodson knew he was not in danger from Gray and should have put a seat belt on the prisoner, he said.

"Before Mr. Gray entered that vehicle, he could walk, he could run ... He could bear his own weight," he said. "After, he was fatally injured because he got in a rough ride."

A seat belt would have saved Gray's life, the prosecutor argued.

"The defendant had the keys to the vehicle," Schatzow said. "No one could get in or out without him."

Graham countered that his client didn't commit any crime and wasn't even involved in Gray's arrest. "The fact that seat belting did not occur with Mr. Gray was the norm, rather than the exception," he said.

The defense argued that Gray kicked and banged around in the back of the van. The prisoner injured himself in what the medical examiner initially termed a "freakish accident," according to Graham.

Baltimore police officer Dennis Smith testified Thursday that it's department policy to place prisoners in seat belts as long as it's safe for an officer to do so. Smith said an officer can use his or her own judgment on deciding whether a prisoner is combative and that he didn't train Goodson on doing so with a combative prisoner.

Smith and Lt. Scott Dressler testified they only taught students how to place belts on prisoners in police cruisers, not transport vans.

Herbert Reynolds, a Secret Service employee who taught a first responder first-aid course, testified he instructed Goodson and many other officers.

Reynolds said most first responders have "limited first aid equipment and training" and that it's not an officer's job to determine whether a prisoner is faking an injury. That's a doctor's job, he testified.

On cross-examination, defense attorney Matt Fraling asked whether an officer has a duty to act if he or she doesn't observe any medical distress. Reynolds said no.

The death of Gray, who was black, ignited a wave of protests as debate surged nationwide over whether police use excessive force, particularly against African-Americans.

Prosecutors have said that Gray complained of having trouble breathing and asked for medical help as he was driven in a police van. When he arrived at a police substation, he was unconscious. A week later, Gray died at a hospital from a spinal injury.

Photos: Baltimore protests People hold hands during a rally at Baltimore City Hall on Sunday, May 3. The death of Freddie Gray, who died in police custody, sparked rioting in Baltimore and protests across the country Hide Caption 1 of 68 Photos: Baltimore protests Members of the National Guard board a truck at an armory staging area on May 3 in Baltimore. After a night of relatively peaceful protests, the city lifted a curfew , the National Guard is preparing its exit and a mall that had been a flashpoint in the protests has been reopened. Hide Caption 2 of 68 Photos: Baltimore protests Medics take a man away after police pepper-sprayed him on Saturday, May 2, in Baltimore's Sandtown neighborhood where Freddie Gray was arrested in April. Hide Caption 3 of 68 Photos: Baltimore protests Police detain a man on May 2 in Baltimore's Sandtown neighborhood. Hide Caption 4 of 68 Photos: Baltimore protests Protesters hold signs on May 2 in the Sandtown neighborhood. Hide Caption 5 of 68 Photos: Baltimore protests Protesters march from the Gilmor Homes housing community, where Freddie Gray was arrested, to City Hall on Saturday, May 2, in Baltimore. Hide Caption 6 of 68 Photos: Baltimore protests Police in riot gear enforce a 10 p.m. curfew and clear Baltimore streets of protesters and media on Friday, May 1. Hide Caption 7 of 68 Photos: Baltimore protests U.S. Rep. Elijah Cummings, D-Maryland, helps clear Baltimore streets of protesters on May 1. Hide Caption 8 of 68 Photos: Baltimore protests Demonstrators celebrate the announcement that six officers were charged May 1 in Gray's death. Hide Caption 9 of 68 Photos: Baltimore protests Demonstrators march through the streets of Baltimore after the charges against the officers were announced May 1. Hide Caption 10 of 68 Photos: Baltimore protests Police on horseback block a Baltimore street on May 1. Hide Caption 11 of 68 Photos: Baltimore protests A demonstrator celebrates in Baltimore the charges were announced on May 1. Hide Caption 12 of 68 Photos: Baltimore protests A member of the National Guard stands outside Baltimore City Hall as protesters gather on Wednesday, April 29. Hide Caption 13 of 68 Photos: Baltimore protests High school and college students march from Baltimore's Penn Station to City Hall on April 29. Hide Caption 14 of 68 Photos: Baltimore protests A community organizer later identified as Joseph Kent paces in front of riot police with his hands up during a curfew in Baltimore on Tuesday, April 28. Moments later, he was seen being arrested by police live on CNN . Kent's lawyer said on April 30 that his client had been released from jail. While some protesters defied the curfew and faced off with police, demonstrations Tuesday were largely peaceful. Hide Caption 15 of 68 Photos: Baltimore protests State Sen. Catherine E. Pugh embraces a protester while urging the crowd to disperse ahead of the 10 p.m. curfew. Hide Caption 16 of 68 Photos: Baltimore protests People attempt to stop protesters from approaching a police line on April 28. Hide Caption 17 of 68 Photos: Baltimore protests A Baltimore police captain tries to calm a protester on April 28. Hide Caption 18 of 68 Photos: Baltimore protests Two women sweep up the streets in Baltimore -- reflected in the broken window of a storefront on April 28. See more photos of the cleanup efforts. Hide Caption 19 of 68 Photos: Baltimore protests A band plays music during protests on April 28 in Baltimore. Hide Caption 20 of 68 Photos: Baltimore protests A boy in Baltimore offers water to a police officer on April 28. Hide Caption 21 of 68 Photos: Baltimore protests Jerrie Mckenny, left, and her sister Tia Sexton embrace as demonstrators hold hands and sing the hymn "Amazing Grace" in Baltimore on April 28. Hide Caption 22 of 68 Photos: Baltimore protests Demonstrators stand in front of a police line and call for peace after a bottle was thrown on April 28. Hide Caption 23 of 68 Photos: Baltimore protests Maryland National Guardsmen patrol the streets on April 28. Hide Caption 24 of 68 Photos: Baltimore protests The remains of a senior center smolder on April 28. Riots broke out Monday, April 27, after Freddie Gray's funeral Hide Caption 25 of 68 Photos: Baltimore protests Police retreat from burned-out cars in an intersection on Monday, April 27. Hide Caption 26 of 68 Photos: Baltimore protests Firefighters respond to a burning building during the riots late April 27. Hide Caption 27 of 68 Photos: Baltimore protests A police officer walks by a burning building on April 27. Hide Caption 28 of 68 Photos: Baltimore protests Police stand guard on April 27. Hide Caption 29 of 68 Photos: Baltimore protests Protesters climb on a destroyed Baltimore Police car in the street near the corner of Pennsylvania and North avenues on April 27. Hide Caption 30 of 68 Photos: Baltimore protests A mixture of milk and water rolls down a man's chest after he was pepper sprayed by the Baltimore Police April 27. Hide Caption 31 of 68 Photos: Baltimore protests A man rides a bicycle through heavy smoke emitting from a nearby store on fire April 27. Hide Caption 32 of 68 Photos: Baltimore protests A man shouts for calm as protesters clash with police April 27. Hide Caption 33 of 68 Photos: Baltimore protests Police carry an injured officer from the streets near Mondawmin Mall in Baltimore on April 27. Hide Caption 34 of 68 Photos: Baltimore protests People carrying goods leave a CVS pharmacy near Pennsylvania and North avenues on April 27. Hide Caption 35 of 68 Photos: Baltimore protests A demonstrator raises his fist as police stand in formation on April 27. Hide Caption 36 of 68 Photos: Baltimore protests Armored cars drive down Pennsylvania Avenue as looters break into shops on April 27. Hide Caption 37 of 68 Photos: Baltimore protests People lock arms and form a line opposing police at the corner of Pennsylvania and North avenues on April 27. Hide Caption 38 of 68 Photos: Baltimore protests Police form a barrier between protesters and a burning CVS being attended to by firefighters on April 27. Hide Caption 39 of 68 Photos: Baltimore protests People carry goods out of a CVS pharmacy on April 27. Hide Caption 40 of 68 Photos: Baltimore protests A police vehicle burns April 27. Hide Caption 41 of 68 Photos: Baltimore protests A police officer throws an object at protesters on April 27. Hide Caption 42 of 68 Photos: Baltimore protests A man carries items from a store as police vehicles burn on April 27. Hide Caption 43 of 68 Photos: Baltimore protests A police officer checks on a man who was injured on April 27. Hide Caption 44 of 68 Photos: Baltimore protests A police officer is carried to safety after being hit in the head with a rock during the riot on April 27. Hide Caption 45 of 68 Photos: Baltimore protests A police officer uses pepper spray on rioters on April 27. Hide Caption 46 of 68 Photos: Baltimore protests Police officers push back a protester on April 27. Hide Caption 47 of 68 Photos: Baltimore protests Police react during the riot on April 27. Hide Caption 48 of 68 Photos: Baltimore protests Baltimore police officers in riot gear look toward protesters near Mondawmin Mall on April 27. Hide Caption 49 of 68 Photos: Baltimore protests Baltimore Police Commissioner Anthony Batts chases away protesters in a parking lot on April 27. Hide Caption 50 of 68 Photos: Baltimore protests A woman abandons her car in the middle of an intersection as Baltimore Police officers clash with protesters outside the Mondawmin Mall in Baltimore on April 27. Hide Caption 51 of 68 Photos: Baltimore protests Police handle the protesters during a riot on April 27. Hide Caption 52 of 68 Photos: Baltimore protests A demonstrator taunts police on April 27. Hide Caption 53 of 68 Photos: Baltimore protests Protesters stand off with police during a march in honor of Gray in Baltimore on Saturday, April 25. Hide Caption 54 of 68 Photos: Baltimore protests A protester throws a barricade at a bar near Oriole Park at Camden Yards after a rally on April 25. Hide Caption 55 of 68 Photos: Baltimore protests Protesters chase after a car as it drives in reverse after the rally on April 25. Hide Caption 56 of 68 Photos: Baltimore protests A protester breaks a store window after the rally in Baltimore on April 25. Hide Caption 57 of 68 Photos: Baltimore protests Protesters get into a shoving match with police during a march downtown on April 25. Hide Caption 58 of 68 Photos: Baltimore protests Protesters and police square off April 25. Hide Caption 59 of 68 Photos: Baltimore protests Protesters drive through the Camden Yards area on April 25. Hide Caption 60 of 68 Photos: Baltimore protests Members of the Baltimore Police Department stand guard Thursday, April 23, outside the department's Western District station during a protest. Hide Caption 61 of 68 Photos: Baltimore protests A police officer films protesters from the steps of the Western District station on April 23. Hide Caption 62 of 68 Photos: Baltimore protests Empowerment Temple Pastor Jamal Harrison Bryant speaks in front of City Hall in Baltimore on April 23. Hide Caption 63 of 68 Photos: Baltimore protests Demonstrators put their fists in the air during a protest outside the Baltimore police's Western District station on Wednesday, April 22. Hide Caption 64 of 68 Photos: Baltimore protests Hundreds of demonstrators march toward the Western District station on April 22. Hide Caption 65 of 68 Photos: Baltimore protests People march through the streets of Baltimore on April 22. Hide Caption 66 of 68 Photos: Baltimore protests Demonstrators argue with Baltimore officers during the protest on April 22. Hide Caption 67 of 68 Photos: Baltimore protests A woman is comforted during the protest on April 22. Hide Caption 68 of 68

Judge Barry Williams has a reputation of being fair but blunt.

The verdict in the Nero case drew mostly outrage on social media but praise from police and the Gray family attorney.

Goodson was scheduled to stand trial earlier this year, but the case was delayed.

Three other officers have yet to stand trial -- Officer Garrett Miller, Lt. Brian Rice and Sgt. Alicia White.

Rice's trial will start July 5, Miller's on July 27 and White's on October 13. Porter is to be retried in September.

CORRECTION: An earlier version of this story incorrectly stated when Officer William Porter will be retried. It will be in September.