As hundreds walked through Baltimore on Thursday to protest a police shooting in Missouri, uniformed officers were recording their every move.
The decision by the Baltimore Police Department to record the march raised questions about how the tapes would be used and why authorities had chosen to record the event. Participants said they saw as many as a dozen officers shadowing the crowds and filming them, almost like a documentary crew, as the protesters walked to the Inner Harbor or spoke with officers.
"They police didn't violate anyone's rights, but what does it mean that these pictures are being taken?" said activist C.D. Witherspoon. "It had nothing to do with security, because there were tons and tons of officers there."
The Police Department declined to discuss the issue but put out a statement saying filming such events is now considered a "best practice" for law enforcement agencies, and said the tapes would be used for training purposes. Nationally, the Police Executive Research Forum, an influential think tank, has been advising departments to film events to protect officers from false claims and to review officers' actions.
David Rocah, a staff attorney for the American Civil Liberties Union of Maryland, said he has concerns about the department's rationale.
"When police are recording demonstrators, they're recording people exercising their First Amendment rights, [which] can itself be intimidating and could lead to police creating a database of who is protesting what. And if it was used in that way, it would be wrong, unconstitutional and deeply disturbing," Rocah said.
The Police Department said making a recording is "a way to document all aspects of an event."
"The recordings document officers' actions, commands given to units, and interactions between police and members of the public," the statement said. "Recordings of the public can be used for training, documenting, and ensuring the highest professional standards of officers involved in protecting large-scale gatherings and events."
Lt. John Kowalczyk, the department's chief spokesman, said officials were drafting procedures to govern the practice. "You will see us continuing to film at large scale events such as New Year's Eve," he said in an email.
A 2011 report by the Police Executive Research Forum recommends that police officials not "be afraid to record video of major events, including your own officers."
"Having your own video recordings is critical to reviewing officers' actions," the report says, adding that citizens and the news media will be filming and "may edit recordings to create false impressions or show incidents out of context."
Philadelphia Police Commissioner Charles Ramsey says in that report that when he was chief of police in Washington, police didn't want to film for fear of capturing "something that we didn't want to see." But he said having an independent account of anything that transpired was more important.
The New York Civil Liberties Union contends police can't legally record protesters unless "it reasonably appears that unlawful conduct is about to occur, is occurring or has occurred." It says it is investigating how New York police use video recordings.
Seattle police recommend video units "for events where intelligence indicates that civil disobedience or crowd violence will occur" and has guidelines for how recordings are handled, according to the department's website. In Washington, police have rules outlining how to log and store recordings of any "mass demonstration or protest."
The ACLU of Maryland sued the Maryland State Police in 2008 to get records about covert infiltration and documentation of peace activists and anti-death penalty groups, which showed that police kept logs and entered some names into a database of people thought to be drug traffickers or terrorists.
The civil rights group has advocated for the rights of citizens to record police interactions, and for the use of body cameras on officers, though it has some concerns about the practice.
Rocah questioned why city police filmed the protest as opposed to other types of incidents handled by officers.
"The view that protesting is itself somehow an inherently disorderly or problematic activity is troubling and the wrong attitude for police to take," Rocah said.
But he saw few problems with police recording the crowds for the purpose of having evidence if a disturbance were to take place, and he acknowledged that rolling cameras were likely to improve the behavior of everyone involved.
"That's part, certainly not all, of why we think it's important for citizens to have the right to record police. The turnabout is true as well," he said.
Cameras have become more common in American policing, as has the debate over how and when to use them. Many police officials and police critics have been pushing for officers to wear body cameras, which would lead to police recording most citizen interactions.
Just a few years ago, Baltimore police were being sued over their policies regarding the right of citizens to film officers, and the Justice Department came down on the Baltimore force, urging it to adopt better rules and training affirming such rights.
Baltimore's downtown area and many neighborhoods have also become peppered with surveillance cameras. Police have also been linking private cameras into their ever-growing network.
State police sometimes use dashboard cameras to record stops — state police posted this week a dashcam video of a trooper stopping a man from jumping off a bridge in Cecil County.
Police Commissioner Anthony W. Batts has indicated he is generally in favor of the body cameras, though he has expressed concerns about logistics, such as how data would be retained and when it would be appropriate for the cameras to be shut off so officers can handle delicate situations.
"I don't like car videos; I like cameras on officers," Batts told residents at a recent community meeting. "The citizen complaints drop off the table."
The agency also in recent years began video recording suspect and witness interviews in homicide and sexual assault cases.
But filming of city police actions on the street generally does not occur, which is why the filming of the protesters caught the eye of participants and reporters.
In Ferguson, Mo., where the community is reeling over the shooting of an unarmed teenager by police, many believe protests escalated when police arrived wearing camouflage and training rifles on the crowd.
There were no incidents reported at the Baltimore protest, in which some participants also drew attention to the deaths of black men and boys after interactions with police here. Beforehand, police had set up barricades around City Hall, had a helicopter assigned to the protests, and deployed dozens of officers to stand guard along the protest route.
One video from the protest posted to YouTube shows a conversation between Lt. Col. Melissa Hyatt and an activist as she cautions him against leading the group through Harborplace. The interaction is being filmed from multiple angles — the person who posted it online, as well as the police cameraman over Hyatt's shoulder.
Witherspoon, one of the organizers of Thursday's march, said he's held multiple protests that were peaceful and has never seen officers filming them before. When his wife asked an officer why they were filming, Witherspoon said the officer took her picture but didn't answer her question.
"It wasn't unconstitutional, but it doesn't pass the smell test," Witherspoon said.
Theresa Dower, 33, took part in Thursday's protest and said she was initially unnerved and "a little bit intimidated" by the officers with cameras. "Is everybody that was here in a file now?" she said she thought. But, she said, she later concluded that local police likely didn't have such capabilities and were "watching their own interactions as much as anything."
Payam Sohrabi, 24, said he wants police to wear body cameras to record interactions with the public and improve transparency, and thought police using cameras was a decent first step.
"I thought it was really just to try to make sure they caught us in case we did anything stupid. But we weren't planning on doing anything," Sohrabi said.