For the second time this year, a cellphone video is raising questions about the conduct of Bay Area Rapid Transit (BART) police.
The video, circulated on YouTube and other websites, shows an officer arresting a disorderly passenger at a station in Oakland, Calif., on Saturday evening. The police officer grabs the man and hauls him out of the train, holding the man's head down. In the video, the officer appears to push the man against the glass barrier, shattering the glass and injuring both officer and suspect.
The incident has revived the intense scrutiny the agency has faced since one of its officers was caught on camera in a fatal shooting of a passenger on New Year's Day.
The latest video leaves little doubt that passenger Michael Gibson was acting unruly, but the question of whether the BART officer, whose name has not been released, used excessive force remains open. The video shows the officer leading Mr. Gibson toward a glass barrier, but it's unclear exactly how the glass broke.
BART officials cautioned anyone from jumping to conclusions.
"This is a use-of-force case that we will thoroughly investigate," BART Police Patrol Commander Daniel Hartwig said in a statement. "In all use-of-force investigations we determine whether the force required to take a suspect into custody is justified and within our use-of-force policy."
The YouTube video – titled "Officer breaks window with drunks face" – had been viewed more than 7,000 times as of Monday morning and has sparked heated debate online.
"The cop barely pushed him. It just happened to be plate glass instead of shatterproof stuff. That dude had a potential weapon in his hand and appeared very aggressive. I challenge any critics to try handling a situation like that differently," commented YouTube user DirkaMuhamud.
Another commenter countered: "It's hard for me to believe that BART still hasn't learned its lesson. This is excessive and that cop should be fired!"
This is how BART explains the encounter: "The officer removed the suspect from the train and led him to the platform wall in an attempt to place him under arrest. During that attempt, the heavy-duty glass portion of the wall was broken and showered down on the officer and the suspect."
On the video, another passenger can be heard saying: "This cop is doing his job. That guy is out of line."
The video that was posted on YouTube will undoubtedly play a key role into the investigation of the incident. When video of the New Year's Day shooting surfaced online, it prompted a massive outcry against BART and against the officer, Johannes Mehserle, who shot and killed 22-year-old Oscar Grant III.
Mr. Mehserle was arrested on murder charges in January and will be tried in Los Angeles after a judge ruled he couldn't get a fair trail in the Bay Area.
Videos can provide indispensable evidence of an incident such as Saturday's arrest at the West Oakland BART station, but they can often be inconclusive, too.
"You've got to have all the evidence in the case. What people were thinking, what people heard, what's going on outside the camera frame," Dan Kahan, a Yale law professor, told the Monitor earlier this year.
Professor Kahan led a study showing how race, culture, and ideology cab can influence a person's impressions of these sorts of videos. That paper focused on a specific video used to settle a Supreme Court case but could also apply to the video of Saturday's BART arrest.
"If there's one lesson in this [study], it should be that we don't make the mistake of thinking that the tape speaks for itself," Kahan said.
Since the January fatality, BART officials have realized the power of viral video.
"We are keenly aware of what YouTube brings to the public," Mr. Hartwig said at a Sunday press conference. "We want to assure the public that we are moving forward. We are not waiting. We are investigating this to the fullest extent."
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