The July 2008 footage drew more than 2.1 million online views before jurors saw it and another witness' video Monday, at the start of Patrick Pogan's trial on charges of assaulting a bicycling activist and lying about it.
Nearly 20 years after an amateur tape of Los Angeles officers beating driver Rodney King sparked a national outcry, Pogan's trial showcases the growing prevalence of witness and surveillance video in law enforcement in an era of YouTube and cell-phone cameras. But Pogan's case also is examining how complete a story such videos tell.
Prosecutors paint the videos as evidence that he summarily body-checked the cyclist to the ground. Pogan's lawyer says the clips don't show the full picture of what happened.
Four officers were acquitted of criminal charges in the 1991 King beating, igniting a riot that killed more than 50 people. In the years since, videotapes of police activity have sometimes implicated suspects and exonerated officers - and at other times have suggested the opposite.
"It's very hard for offenders to commit crimes without being captured, either on a surveillance camera or a cell phone," James Alan Fox, a criminologist at Northeastern University. But the ever-expanding corps of cameras also means officers' "behavior is constantly being recorded, and that might be a potential minus."
In Maryland, two Prince George's County officers were suspended after a March 3 video taken by a University of Maryland student from a dorm room window appeared to show an unprovoked attack on a student during a rowdy post-game celebration.
The tourist's video in the Pogan case shows the then-rookie officer striding toward a participant in a pro-cycling demonstration and shoving the rider off his bike on July 25, 2008. The cyclist, Christopher Long, began running from officers, who wrestled him into handcuffs. He wasn't seriously hurt.
The other video, shot by another cyclist riding behind Long, doesn't show the moment Pogan made contact with him but shows the officer seeming to single him out among a stream of people riding past.
Pogan's report said Long purposefully rammed him. The cyclist was charged with resisting arrest and other offenses.
Then sponsors of the cycling demonstration paid Florida tourist Asam Ismail $310 for his video and posted it on YouTube.
The charges against Long were dropped. Pogan, who resigned from the force in February 2009, is charged with offenses including assault and falsifying business records.
"Not only did (Pogan) push Christopher Long off his bike - he pushed him right into New York's criminal justice system," Manhattan Assistant District Attorney Ryan Connors told jurors in an opening statement.
Defense lawyer Stuart London said Pogan just acted on instructions to stop cyclists if they broke traffic rules during the freewheeling monthly demonstration, known as Critical Mass.
A supervisor wrote Pogan's report, London said. And he said Long - who sued the city and reached a $65,000 settlement over the incident- ignored a signal to halt, made an obscene gesture and otherwise "orchestrated" the confrontation in ways the videos don't show.
"The video does not give you a 360-degree view of what happened here," London said in his opening statement.
Long's lawyer, David B. Rankin, didn't immediately return a call Monday.
Pogan, 24, faces up to four years in prison if convicted.
Both police and civil liberties advocates generally agree the spread of video cameras has proven useful.
Police in New York, Dallas and other places have installed video cameras on patrol cars' dashboards to document arrests and traffic stops. Investigators increasingly turn to surveillance footage and cell phone cameras to capture suspects and build cases; the New York Police Department solicits video clips as tips.
Meanwhile, "there's no question but that video evidence gives ordinary people enormous boosts in credibility when confronting contradictory police evidence," said Donna Lieberman, executive director of the New York Civil Liberties Union.
But video can raise questions as well as answer them, experts say. What happened before the "record" button was pressed? Who shot it, and why? What did it look like from another point of view?
"Clearly, (a video's) one piece of documentation is not everything that happened," said Pat Aufderheide, a documentary film expert and director of American University's Center for Social Media. "But it's a representation that, in general, people know how to read."