Black men who try to avoid an encounter with Boston police by fleeing may have a legitimate reason to do so — and should not be deemed suspicious — according to a ruling by the Massachusetts Supreme Judicial Court.

Citing Boston police data and a 2014 report by the ACLU of Massachusetts that found blacks were disproportionately stopped by the city's police, the state’s highest court on Tuesday threw out the gun conviction of Jimmy Warren.

Warren was arrested on Dec. 18, 2011, by police who were investigating a break-in in Roxbury. Police had been given a description of the suspects as three black men — one wearing a “red hoodie,” one wearing a “black hoodie” and the other wearing “dark clothing.” An officer later spotted Warren and another man (both wearing dark clothing) walking near a park. When the officer approached the men, they ran. Warren was later arrested and searched. No contraband was found on him, but police recovered an unlicensed .22 caliber firearm in a nearby yard. Warren was charged with unlawful possession of a firearm and later convicted.

In its ruling, the court made two major findings: The justices said police didn’t have the right to stop Warren in the first place, and the fact that he ran away shouldn’t be used against him.

On the first point, the court said the description of the break-in suspects’ clothing was “vague,” making it impossible for police to “reasonably and rationally” target Warren or any other black man wearing dark clothing as a suspect. The court said the “ubiquitous” clothing description and the officer’s "hunch" wasn’t enough to justify the stop.

"Lacking any information about facial features, hairstyles, skin tone, height, weight, or other physical characteristics, the victim's description 'contribute[d] nothing to the officers' ability to distinguish the defendant from any other black male' wearing dark clothes and a 'hoodie' in Roxbury."

On the second point, the court noted that state law gives individuals the right to not speak to police and even walk away if they aren’t charged with anything. The court said when an individual does flee, the action doesn't necessarily mean the person is guilty. And when it comes to black men, the BPD and ACLU reports “documenting a pattern of racial profiling of black males in the city of Boston” must be taken into consideration, the court said.

"We do not eliminate flight as a factor in the reasonable suspicion analysis whenever a black male is the subject of an investigatory stop. However, in such circumstances, flight is not necessarily probative of a suspect's state of mind or consciousness of guilt. Rather, the finding that black males in Boston are disproportionately and repeatedly targeted for FIO [Field Interrogation and Observation] encounters suggests a reason for flight totally unrelated to consciousness of guilt. Such an individual, when approached by the police, might just as easily be motivated by the desire to avoid the recurring indignity of being racially profiled as by the desire to hide criminal activity. Given this reality for black males in the city of Boston, a judge should, in appropriate cases, consider the report's findings in weighing flight as a factor in the reasonable suspicion calculus."

The SJC concluded that police lacked reasonable suspicion for an investigatory stop in this case.

Matthew Segal, the legal director of the ACLU of Massachusetts, called the decision "a powerful ruling" that demonstrates what role courts can play in addressing community concerns about policing.

"The state’s highest court, in talking about people of color, it’s saying that their lives matter and under the law, their views matter," Segal said. "The reason that’s significant is that all the time in police-civilian encounters there are disputes about what is suspicious and what is not suspicious. So this is an opinion that looks at those encounters through the eyes of a black man who might justifiably be concerned that he will be the victim of profiling."

The ACLU's report found that between 2007 and 2010, 63 percent of Boston police encounters were with blacks, though at that time the city's black population was just 24 percent. Notably, the report said that taking into account high-crime neighborhoods did not explain the disparity.

Boston Police Commissioner Bill Evans blasted the SJC ruling and said he was "troubled" the court cited the ACLU report, which he called "heavily tainted against the police department."

"I think they relied heavily on an ACLU report that I think was clearly way out of context," Evans told reporters Tuesday. "I’m a little disappointed that they relied heavily on a report that didn’t take into context who was stopped and why. That report clearly shows that we were targeting the individuals that were driving violence in the city and the hot spots."

The SJC ruling also cited the Boston Police Department's own analysis, which found blacks were 8 percent more likely to be stopped repeatedly and 12 percent more likely to be searched and frisked even when controlling for factors like criminal history, gang affiliation and violent crime areas.

Evans said the department's report found there was no indication of bias. The department's report did outline steps to ensure fair stops, including increased training on racial profiling and unconscious bias.

The SJC ruling comes a week after the launch of a long-awaited police body camera pilot program in Boston -- a program many, including Segal, see as a positive step toward police accountability and transparency. Body cameras have been part of a larger national conversation on policing since the 2014 fatal shooting of Michael Brown in Ferguson, Missouri, and other high-profile police shootings of unarmed black men across the country.

WBUR's Delores Handy contributed reporting.