New York - A surveillance video released by New York police shows former tennis star James Blake being slammed to the ground and handcuffed by an undercover officer.
Blake appears to have been caught by surprise as he is casually leaning against a beam outside his hotel, and does not resist arrest, according to the minute-long video released by the New York Police Department on Friday.
It appears to confirm Blake's account of the rough actions taken by the officer.
Blake, who is biracial, said he was detained for 15 minutes and that he suspects a "racial factor" was involved in his brief detention. Police denied race was a factor, insisting it was a case of mistaken identity.
The city's top police officer and mayor have already apologized to Blake, 35, for the incident.
In a statement, Blake vowed to "use my voice to turn this unfortunate incident into a catalyst for change in the relationship between the police and the public they serve."
He called for the city to make a "significant financial commitment."
In a joint statement, NYPD Commissioner William Bratton and Mayor Bill de Blasio said the incident was under investigation "to determine what contributed to the errors made, who may be held accountable and what we can learn to prevent these mistakes from being repeated in the future."
The city has already invested nearly $29 million (25.6 million euros) to retrain some 22,000 uniformed law enforcement officers, the statement added.
And new neighborhood policing efforts have seen civilian complaints against police drop to their lowest levels in 14 years.
The New York Times reported that the officer who stopped Blake - James Frascatore - already had a history of excessive force complaints, including two violent altercations with black men.
He was promptly stripped of his badge and gun, and placed on desk duty pending the outcome of the investigation.
Former world number four Blake was in town to make endorsement appearances at the US Open and was met by a group of police officers - all of them white - just outside his Manhattan hotel, who sought a person in connection with a fraud case.
Blake said he had suffered cuts to his leg and elbow during the incident.
"It was definitely scary and definitely crazy," Harvard-educated Blake told the New York Daily News.
"In my mind there's probably a race factor involved, but no matter what there's no reason for anybody to do that to anybody... It's blatantly unnecessary."
Blake won 10 titles in his career, making almost $8 million. He last played on the tour in 2013.
The US Tennis Association expressed its concern over the incident and its support for Blake.
"The USTA is deeply concerned about this troubling incident," it said.
"James is the embodiment of a model citizen whose triumphs on and off the court continue to inspire tennis fans and non-fans alike."