According to pg 244 of the Fletcher Genealogy by Edward H. Fletcher Related to the Unrelated Line of Pendleton Fletcher
Brian who married Amy Pettengill d June June 24 1824.She died Jan 6 1835 Their daughter Sarah is listed as born April 24 1790.
The Fletcher Genealogy shoes that David m Esther Deniston and had no daughters named Sarah
Robert married Mary Church and had no Sarah.
Robert, Brian, David are sons are sons of Brian Fletcher and Anna Young . Their sister Mary Fletcher married Daniel Savage as his second wife in Hallowell. My grandfather on several lines connected to the Savages. Daniel Savage who married Married Mary Fletcher was his 2nd great uncle. Luckily the Fletcher is Unconnected or I would be dealing with a link with with the Fletcher Line that adopted my grandmother (the Robert Fletcher Line)
You could be looking at a descendant of Robert Fletcher that mage it to Maine. Several werein Hallowell or Kennebec County. Skowehegan and Norridgewock are two places you might look. You can find the Fletcher Genealogy on Ancestry or public domain.