New Jersey State Police said in a statement that the body found 10 p.m. Monday in Clayton is that of Autumn Pasquale, who was last seen on Saturday.
Officials did not say exactly where the body was found. An autopsy will be conducted Tuesday morning by the Gloucester County Medical Examiner's office, officials said.
Pasquale was reported missing from her Clayton home at 9:30 p.m. Saturday, and had been the subject of a large search over the last two days.
Investigators with the prosecutor's office found the body shortly after an emotional candlelight vigil was held for the girl in her hometown.
Bernie Weisenfeld, spokesman for the Gloucester County Prosecutor's office, said Pasquale's family was notified of the discovery.
"This is a very sad day for the Pasquale family," Gloucester County Prosecutor Sean F. Dalton said in a statement. "Our hearts go out to the family and to all the residents of Clayton who stood together in support of this young girl."
No other information was released, and officials continued their investigation through the night.
About 200 law enforcement officials and hundreds more volunteers had searched Monday for Pasquale.
Dalton had said Monday afternoon, 48 hours after anyone had heard from the girl, that 75 people had been interviewed. At that time, investigators didn't have any suspects or a sure sense of whether the quiet BMX biking enthusiast had left on her own or was the victim of foul play.
With the girl's parents flanking him while holding back tears at an afternoon news conference, Dalton announced a $10,000 reward for information leading authorities to the girl. The parents - Anthony Pasquale and Jennifer Cornwell - did not speak at the news conference. Both wept during the evening vigil.
Authorities said Autumn, whose 13th birthday is Oct. 29, was last seen around 12:30 p.m. Saturday pedaling her white bicycle away from the Clayton home where she lives with her father, her two siblings, her father's girlfriend and the girlfriend's children.
A friend, 11-year-old DeAnna Edwards-McMillen, said Autumn was at her house Friday night and they exchanged text messages on Saturday. She said she received the last one at 1:22 p.m. and didn't believe it was intended for her. She said it read, "don't be like that."
DeAnna said her friend was nice and easy to be around. "She didn't hate people," she said in a tearful interview with The Associated Press, "and people didn't hate her."
DeAnna's mother, Debi McMillen, said that Autumn was often at their house and that she always went home before her 8 p.m. curfew.
The last known communication was in a text message she sent around 2:30 p.m. Dalton would not say who received the message or what it contained. But he said that there was nothing alarming or unusual about it.
It wasn't until about 9:30 p.m. that she was reported missing - 90 minutes past her 8 p.m. curfew, said Paul Spadofora, a family spokesman, the uncle of Autumn's father and the girl's godfather.
Dalton said 50 county and local law enforcement officers were on the case shortly after she was reported missing.
By Monday, the number grew fourfold as FBI and state police got involved in a search that has employed helicopters, horses, bloodhounds and computer experts. The computer experts were charged with seeing if any information about her whereabouts shows up on Facebook or elsewhere online.
Dalton said investigators accounted for all the registered sex offenders in the area, interviewed them and were searching their properties.
The weary crew of volunteers, meanwhile, was looking in area malls, handing out fliers at intersections in Clayton's tiny downtown and searching wherever they could.
Early Monday, Weisenfeld said the girl's bike had not been found. By the afternoon, Dalton would not say whether it had been located.
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