The Baltimore police officer who drove the transport van Freddie Gray rode in after his arrest was found not guilty on Thursday of all charges stemming from Gray's April 2015 death, making him the third officer in that case tried without a conviction.

Officer Caesar Goodson faced charges of second-degree "depraved heart" murder, manslaughter, second-degree assault, misconduct in office and reckless endangerment resulting from the broken neck Gray suffered while in police custody. Gray's death one week after his arrest set off racial unrest across the city.

Baltimore police said they were ready for possible protests after the verdict and the Maryland National Guard was on standby.

Circuit Judge Barry Williams read the verdict to a packed courtroom. Goodson was facing the most serious charges out of the six officers accused in Gray's death. Goodson opted for a bench trial leaving his fate up to Judge Williams.

Goodson was dressed in a black suit. After the verdict was read, he was greeted by friends and relatives, many of whom were crying. Officer Edward Nero, who was acquitted last month, sat in the front row and hugged Goodson.

Prosecutors alleged that Gray sustained his injuries because Goodson did not properly strap Gray into the police van on April 12, 2015 and also gave him a “rough ride” on the way to the police station. The charges could have sent Goodson to prison for at least 68 years.

Judge Williams repeatedly said prosecutors failed to show evidence that Goodson was aware or should have been aware that Gray was hurt. He also said they could not prove how Gray's injuries occurred.

State's Attorney Marilyn Mosby was seated in the center of the front row. After the verdict was announced she sighed and walked out of the courtroom with a security entourage.

Gray was arrested after running from an officer on bike patrol outside a public housing project not far from the Western District station house. He was later found with an illegal knife. A neighbor's video showed him handcuffed behind his back and hoisted into Goodson's van.

The van made a total of six stops that day, and Gray was unresponsive on arrival at the station house 45 minutes later. Prosecutors said Goodson was there throughout and checked on Gray during the third and fourth stops, so he should have known Gray was in distress.

They said his failure to call a medic amounted to murder.

A prosecution expert testified that Gray could not possibly have broken his own neck. Prosecutors said the injury happened somewhere between the second and fourth stops, when Goodson and Officer William Porter lifted Gray off the floor.

Porter testified that Gray was lethargic, but could breathe and speak, and didn't seem injured. Prosecutors countered that the initial injury became critical as the trip continued.

Porter was the first officer to face trial. The judge declared a mistrial in December after a jury deadlocked.

Second-degree "depraved heart" murder, which carries up to 30 years in jail, would mean that Goodson was so negligent in his inaction that he cast aside any consideration for Gray's life.

During opening statements, prosecutors for the first time accused Goodson of giving Gray a "rough ride," intentionally leaving him unbuckled "to bounce him around in the back of the van."

But by closing arguments, they all but abandoned the theory, saying Goodson's failure to belt Gray in under the circumstances was sufficient to prove the intent necessary for a murder conviction.

"Officer Goodson never calls a medic, he never takes Freddie Gray to the hospital," said Deputy State's Attorney Jan Bledsoe. "He has breached his duty, and because of that breach Freddie Gray's life was shortened."

The judge seemed skeptical, peppering prosecutors with questions and asking what evidence they had supporting the "rough ride" theory. What if Gray had emerged from the van unhurt, despite being unbuckled, and was found to be falsely claiming injury in order to avoid jail?

Chief Deputy State's Attorney Michael Schatzow said the failure to belt him in would still be a crime, although a difficult one to prosecute.

Goodson's attorney Matthew Fraling fiercely rejected the allegations, telling the judge that Goodson was a "gentle" officer who didn't buckle him in because Gray was exhibiting "violent and erratic" behavior, citing witness testimony that he was making the wagon shake back and forth by kicking and flailing inside.

Fraling also said Gray said "yes" when Porter asked if he wanted to go to a hospital only because Gray hoped to avoid jail.

"They have failed to cobble together any type of case with reasonable inferences, let alone evidence," he said. "The mere fact that harm resulted doesn't mean the Officer Goodson's conduct is the cause of that harm."

Lt. Brian Rice's trial is set to begin in July, followed later in the month by Officer Garrett Miller, Porter's retrial in September and Sgt. Alicia White's trial in October.

Fox News' Michelle Macaluso, Courtney Stein Vargas and The Associated Press contributed to this report.