Olivia Colby, of Westborough, vanished on Thursday, March 14, sparking a near-statewide search.
The Worcester County District Attorney's Office did not say how she died, where she was found, or how long she had been deceased in their announcement on Friday.
There was some hope in the case Monday when a man told police he believed he saw Colby at Kennebunk Cumberland Farms in Maine, but that alleged sighting led nowhere, according to an NBC station in Maine.
Investigators said Colby's phone was last used near her family's 21 Mountain View Drive home in Westborough on the day she went missing.
A flyer handed out by searchers said "There are concerns for her current well-being." Though they did not go into what those concerns could be.
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