NEW YORK (Reuters) - An Occupy Wall Street protester was found guilty on Monday of assaulting a police officer during a demonstration two years ago to mark the protest movement's six-month anniversary in New York City.

A New York jury found Cecily McMillan, 25, guilty of elbowing a police officer, Grantley Bovell, in the eye as he was attempting to arrest her. McMillan's lawyer argued that his client was reacting to someone groping one of her breasts, according to media accounts of the trial.

McMillan's lawyer did not immediately reply to a request for comment. McMillan came to New York after college to volunteer with the labor group the Democratic Socialists of America, according to the New York Times.

New York State Court Justice Ronald Zweibel ordered her to be held in jail until her sentencing on May 19, a person familiar with the proceedings said on Monday, asking to be anonymous because he was authorized to speak on behalf of the court. McMillan faces up to seven years in prison.

McMillan was arrested along with scores of others on March 17, 2012. While thousands of people were arrested during Occupy protests in 2011 and 2012, most of those cases were dismissed, some were resolved out of court and just 67 have gone to trial.

McMillan is one of 56 people to be convicted at trial, while another 11 people have been acquitted.

Bovell suffered "swelling and bruising and substantial pain to his left eye" as a result of the incident, according to court documents.

The populist movement protesting economic inequality got its start in a downtown Manhattan park. Occupy inspired dozens of spin-offs around the world with its "We are the 99 percent" slogan but drew criticism for its unclear goals.

(Reporting by Edith Honan; Editing by Scott Malone and Richard Chang)

[Image via Agence France-Presse]