Racial bias among Philadelphia police officers may have helped fuel the arrest of two men at a Center City Starbucks in April, and police officials need to better train officers to combat their preconceived notions, according to an examination by the Police Advisory Commission released Monday night.

The commission, a citizen oversight board established in 1994, spent months reviewing the episode that  sparked national outrage and ignited conversations about police practices and racial profiling. The resulting report, released at the commission's Monday meeting, found that "infusing anti-racist principles into the operations of the Philadelphia Police Department may not only help prevent future incidents but can help officers in their day-to-day relationship building."

"The goal for us was to help everyone understand that issues can be nuanced and tinged with race, or affected by race and racism, and the Police Department, often, is the person at the front lines of all of our issues," said Hans Menos, executive director of the commission, "and so it's imperative, or incumbent upon them to understand that, and combat that."

The arrests of two black men at the Starbucks at 18th and Spruce Streets prompted nationwide outrage, protests outside the store, and the departure of the manager who called police to the coffee shop to arrest two men who had been sitting at a table waiting for an acquaintance. They didn't make any purchases. When they refused to leave, a store manager called police, who led them out of the store in handcuffs. No charges were filed, as Starbucks declined to prosecute.

A video of the arrests was posted on Twitter and quickly went viral, sparking outrage nationwide. The video has been viewed more than 10 million times.

The report offered a list of recommendations for anti-racist training that focuses not only on implicit bias, or unconscious bias, but also on systemic racism as the root cause of implicit bias.

"The PPD should accept that racism has a profound effect on what drives citizen and police contact, and should incorporate consistent, anti-racist practice, incident review and training."

In a written response to the report, Police Commissioner Richard Ross said the Police Department rejected the notion that racism drives citizen-police contact.

"Rather, we believe the profound effect on what drives citizen and police contact lies in criminal conduct and victimization. Citizens call and contact the police when they need help or a crime has occurred or is perceived to have occurred," Ross wrote. "We can agree that biases, whether implicit or explicit, may distort the fears and perception of some citizens who call the police to report crimes."

Ross added that the department recognizes that racism exists and "established clear policy in 2011 prohibiting racially biased policing."

"Specifically, officers are not to consider race and/or ethnicity of the suspect or person to be stopped in determining whether there is reasonable suspicion or probably cause sufficient to justify the investigation," Ross wrote. "While officers clearly take into account the reported race or ethnicity of a specific suspect, race and ethnicity can never be used as the sole basis for probable cause or reasonable suspicion."

Commission chair Ronda Goldfein, whose husband, David Lee Preston, is an editor at the Inquirer and Daily News, said a lot of the types of racism mentioned in the report sound like "a no-brainer."

"But it's deeper than that," Goldfein said. "It's about how implicit bias factors into everybody's decision, and whether it factored into the cop's decisions."