By John Drake, Globe Staff
A 16-year-old Wellesley girl was found alive but unresponsive in an Andover creek this morning, several hours after being reported missing from a house party, authorities said.
Andover officials said the girl, a junior at Concord Academy, an independent school in Concord, was in critical condition at a Boston hospital this afternoon.
Lieutenant James Hashem of the Andover Police Department said the girl was reported missing from a house in Andover at 6:50 a.m., nearly two hours after she told people at the party that she was leaving. The other partygoers initially tried to search for her, and called police after they could not find her, Hashem said.
"I think they were concerned because she wasn't from the area and she was leaving on foot," Hashem said.
Hashem said he did not know who was hosting the party or whether adults were present.
Officials from Andover, Methuen and the State Police used canines and a helicopter to search the area, about 20 miles north of Boston.
Officers found the girl submerged in a creek behind Warwick Circle in Andover, in the same neighborhood as the house party.
Officers performed CPR on the scene. She was taken by ambulance to Lawrence General Hospital and then by helicopter to an unspecified Boston hospital.
Authorities are investigating the circumstances of the party.
Globe correspondents Richard Thompson and John Forrester contributed to this report.