A cellphone video of a Metro Transit police officer asking a light-rail passenger about his immigration status went viral Friday, prompting the transit agency to launch an internal investigation.

Minneapolis artist Ricardo Levins Morales posted the video Friday afternoon on Facebook under the heading, “WHY ARE TRANSIT POLICE ASKING RIDERS’ IMMIGRATION STATUS?”

Within three hours, the video had been viewed about 54,000 times and more than 160 people had commented.

Morales said he was returning home Sunday on the Blue Line from Minneapolis-St. Paul International Airport when two Metro Transit police boarded the train and began checking passengers’ fares, which is routine.

“A young man standing in front of me didn’t have a satisfactory answer” when the officer asked for proof that he paid his fare, Morales said. That’s when Morales began filming the interaction, “because these are the kinds of situations that can escalate quickly.”

According to the video, the officer asks the man, “Are you here legally?” Morales then asks the officer, “Are you guys authorized to act as immigration police?”

The officer shrugs and says, “No, not necessarily.”

Morales responds: “Then I would stay out of that. It’s very touchy legal territory.” The officer ultimately shrugs again and says, “OK.”

Morales said he wasn’t sure what happened after the following stop because the crowd dispersed. The Blue Line connects the Mall of America to downtown Minneapolis.

In a statement Friday, Metro Transit Police Chief John Harrington said that once alerted about the video, he “called for an Internal Affairs investigation to gather the details about this incident and to report back to me as quickly as possible.”

Harrington did not name the part-time officer.

“The main priority for our officers is to ensure that our riders and the communities we serve are safe,” he said. Officers enforce local and state laws and “have not been trained or empowered to act as federal immigration authorities.”

In recent months, the presence of U.S. Department of Homeland Security (DHS) police officers on light-rail trains has prompted unease among some passengers. Metro Transit has said the DHS officers are part of a Visible Intermodal Prevention and Response (VIPR) team working with its police force to help ensure security on public trains and buses.

The VIPR officers, who have worked with the agency for more than a decade, do not engage in enforcement actions, Metro Transit said in March. Metro Transit typically tweets advisories if VIPR officers are patrolling the trains.

On Friday, Morales said he was pleased the video was widely disseminated.

“That was my hope. I wanted to make sure it was visible to people who would put pressure on Metro Transit,” he said.

“You can say we’re a sanctuary city, and it’s a nice phrase, but it only has meaning if it actually affects people’s behavior.”