BOSTON (AP) – The death of a 14-year-old girl who died after performing a routine cheerleading stunt was an accident, according to an autopsy report released Thursday.

The report said Ashley Burns died of a laceration of her spleen, caused by blunt abdominal trauma.

Burns, an incoming freshman at Medford Vocational-Technical High School, was practicing with her teammates Tuesday afternoon at a cheerleading camp when four other girls tossed her into the air. She landed chest-first in her friends’ arms, rather than on her back, police said. Soon afterward, she complained of abdominal pain and shortness of breath.

Paramedics took her to Saints Memorial Hospital in Lowell, where she was pronounced dead around 6 p.m.

The girls were practicing a sophisticated but routine stunt called an arabesque double down, in which they held Burns by one foot and tossed her into the air. She was supposed to make two full twirls before landing on her back in the arms of her teammates. But Burns did not make the full rotation and landed instead on her stomach, said her coach, Julie Brown.

Authorities will not investigate the death because it was an accident, according to Melissa Sherman, a spokeswoman for the Middlesex district attorney’s office.