The NYPD put tennis champion James Blake into handcuffs after mistakenly identifying him as a suspect in an identity theft investigation at the Grand Hyatt Hotel in midtown Manhattan Wednesday. 

Blake, who was released after his identity was confirmed, told reporters that he was slammed to the ground by plainclothes officers. The 35-year-old former player, who was once ranked No. 4 in the world, was in town for the U.S. Open and planned to be there all week. 

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"It shouldn't have happened and... it's something that we'll deal with with the police and we'll find out what they have to say internally," Blake said outside the hotel. "Hopefully there's video of it and people can see what happened."

When asked if the cops said anything first he said, " No, (they) just rushed." 

A spokesman for the NYPD said the internal affairs bureau is investigating whether its officers improperly used force when they detained Blake. 

"Once Blake was properly identified and found to have no connection to the investigation, he was released from police custody immediately," the NYPD spokesman said. 

A second person who was also detained remained in custody, police said. That person was not named.