The boyfriend of a Millersville University freshman found dead in her dorm has been charged with murder.

Authorities say that 19-year-old Gregorio Orrostieta called 911 early Sunday and claimed that his girlfriend, 18-year-old Karlie Hall, had suffered a heart attack. Police found Orrostieta administering CPR, which authorities say was “completely fake,” since Hall had been dead for hours.

Orrostiet alleged that he pushed his girlfriend, causing her to fall and hit her head. But an autopsy has found that she was beaten and strangled to death.

Surveillance video confirms that no one else was in Hall’s dorm room at the time that the struggle was heard.

Lancaster County District Attorney Craig Stedman says Hall fought for her life.

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The couple, both from the Philadelphia suburbs, had been dating about 11 months.

Orrostieta, of Kennett Square, is not a Millersville student. He was being held without bail. The prosecutor said he did not have a lawyer on record, and no one answered the door at his residence Monday afternoon.

Orrostieta told police that he and Hall, 18, of Chadds Ford, had argued at a party Saturday night and she had hit him, the affidavit said. They made up before returning to the dorm at around 1:30 a.m. and arguing again, the affidavit said. Stedman declined to say if there was a history of abuse.

Stedman said witnesses reported hearing yelling and the sound of furniture moving between 2 and 2:30 a.m., about the time authorities believe Hall was killed.

The dorm's resident assistant knocked on the door, but no one answered and no further sound was heard, authorities said.

Police found Hall unresponsive when they arrived at Bard Hall after getting the 911 call at about 5 a.m., authorities said.