BOSTON (CBS) – A 17-year-old girl was allegedly raped in front of concertgoers at a sold out show in Mansfield this weekend. Police say some fans just watched, not realizing they were witnessing what the girl says was an assault.

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The attack happened the same night dozens of concertgoers were arrested or treated for alcohol poisoning during the Keith Urban show at the Xfinity Center.

Ambulances from all over the area had to come help bring 46 concertgoers to 22 hospitals, mostly with alcohol problems last Saturday.

Sean Murphy, 18, of West Roxbury, was among more than 50 taken into custody. Mansfield police arrested and charged him with sexually assaulting a 17-year-old girl.

The incident began when a witness approached an officer to report a possible rape on the front lawn of the venue, according to a Mansfield Police statement. According to a police report, a witness told an officer she approached the female who was on the ground and asked her if the “event” was consensual. She allegedly told the witness “no.”

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Then the witness, “saw the female break free and run.” Police, in their statement, said a witness pushed the suspect off of the victim. The suspect then fled into the crowd.

Patrons brought the victim to get help and reunite her with her friends, according to the police statement.

Witnesses gave police a description of the suspect and closed the venue’s gates as they searched for him, according to the police statement. Police located and arrested Murphy.

Witnesses say more than a dozen people looked-on, taking photos. Police are processing those photos as evidence, according to their Facebook post.

Murphy told police it was consensual. According to the police report, Murphy “stressed that he did not force himself on her.”

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Christina Hager