ST. LOUIS — Noisy demonstrators marched through two malls in an upscale area of suburban St. Louis on Saturday to protest the acquittal of a white former St. Louis officer in the shooting of a black man, picking up after a night of mostly peaceful demonstrations that escalated into scattered acts of vandalism and violence. A few hundred people walked through West County Center in Des Peres, an upscale community west of St. Louis, loudly chanting slogans such as "black lives matter" and "it is our duty to fight for our freedom" to decry the judge's verdict Friday clearing ex-St. Louis police officer Jason Stockley of first-degree murder in the 2011 shooting death of Anthony Lamar Smith. Here are the two big questions in the case:

DID THE OFFICER PLANT THE GUN?

The officers were investigating what appeared to be a drug transaction in the parking lot of a fast food restaurant. The car sped away and a high-speed chase ensued. Police slammed their SUV into Smith's car. Stockley then got out and fired five shots into Smith's car, killing him. A handgun was found in the car after the shooting.

Prosecutors argued the presence of Stockley's DNA — and absence of Smith's DNA — on the gun proved the gun must have been planted by the officer. They also noted curious details after the shooting, including Stockley digging into a bag in the back seat of the police SUV before returning to Smith's car.

But the defense countered that Stockley heard his partner yell "gun" and saw the driver's hand on a gun as the car sped by him. Stockley testified he did not draw his service weapon and fire until he saw Smith reaching around inside the vehicle after it was stopped. He said Smith changed his demeanor, suggesting he found the gun.

Stockley testified that after the shooting he found the gun tucked down between the seat and the center console, and he rendered the gun safe by unloading cartridges from the cylinder and then left the gun and cartridges on the passenger seat.

In his ruling, Wilson wrote that "a fact issue that is central" to the case is whether Smith had the gun when he was shot. He found the state's contention that the officer planted the gun is not supported by evidence.

As for Stockley digging around in a bag in the police SUV, Stockley testified that he retrieved a "quick clot" pack, a medical item designed to stop serious bleeding, and put it in his shirt pocket. In the police video showing Stockley looking in the bag, a viewer can't see what he's doing or what he might have taken out of the bag.

The judge found the idea that Stockley took a gun from the police SUV to Smith's car not credible. A full-sized revolver was too large for the officer to hide in his pants pockets and he was not wearing a jacket, the judge said. If the gun had been tucked into his belt, it would have been visible on a bystander's video that showed Stockley walking between the police car and Smith's car, he found.

Wilson also noted none of the officers standing next to the vehicle were called to testify that Stockley planted a gun. And he recounted witness testimony that the absence of a person's DNA on a gun does not mean that person did not touch the gun.

"Finally, the Court observes, based on its nearly thirty years on the bench, that an urban heroin dealer not in possession of a firearm would be an anomaly," the judge wrote.

DID THE OFFICER'S OUTBURST INDICATE PREMEDITATION?

Smith drove at speeds of up to 87 miles per hour on wet roads, endangering other drivers and pedestrians. About 45 seconds before the chase ended, police dashcam video captured Stockley saying, "going to kill this (expletive), don't you know it."

Prosecutors argued that statement proved the officer deliberated about killing Smith even before the pursuit ended.

When questioned about his statement at trial, Stockley said he could not remember saying those words. The ruling noted Stockley testified he had not made a decision to kill Smith and could not recall the context in which the statement was made.

The judge said in his decision that it was apparent from the dashcam audio and video that the pursuit was stressful, both because of its high speed and the confusion caused by multiple radios and communications with the dispatcher.

"People say all kinds of things in the heat of the moment or while in stressful situations, and whether Stockley's statement ... constituted a real threat of action or was a means of releasing tension has to be judged by his subsequent conduct," the judge wrote.

The court does not believe the officer's conduct following the end of the pursuit is consistent with the conduct of a person intentionally killing another person unlawfully, Wilson wrote. He noted testimony by the state's witnesses that Stockley ordered Smith to open the door and show his hands.

It was not until 15 seconds after Stockley arrived the driver's side door that he took his service weapon out of its holster and fired several shots.