Question: What is the body of water by the birthplace of Sandbar Sinister's author?

full_context: Document 1: The Iron Clew: The Iron Clew is a novel that was published in 1947 by Phoebe Atwood Taylor writing as Alice Tilton. It is the eighth and last of the eight Leonidas Witherall mysteries.
Document 2: Boston: Boston has an area of 89.6 square miles (232.1 km2)—48.4 square miles (125.4 km2) (54.0%) of land and 41.2 square miles (106.7 km2) (46.0%) of water. The city's official elevation, as measured at Logan International Airport, is 19 ft (5.8 m) above sea level. The highest point in Boston is Bellevue Hill at 330 feet (100 m) above sea level, and the lowest point is at sea level. Situated onshore of the Atlantic Ocean, Boston is the only state capital in the contiguous United States with an oceanic coastline.
Document 3: Dead Ernest (novel): Dead Ernest is a novel that was published in 1944 by Phoebe Atwood Taylor writing as Alice Tilton. It is the seventh of the eight Leonidas Witherall mysteries.
Document 4: Parker Pyne Investigates: Parker Pyne Investigates is a short story collection written by Agatha Christie and first published in the UK by William Collins and Sons in November 1934. Along with "The Listerdale Mystery", this collection did not appear under the usual imprint of the Collins Crime Club but instead appeared as part of the "Collins Mystery" series. It appeared in the US later in the same year published by Dodd, Mead and Company under the title Mr. Parker Pyne, Detective
Document 5: Charles River Reservation Parkways: The Charles River Reservation Parkways are parkways that run along either side of the Charles River in eastern Massachusetts. The roads are contained within the Charles River Reservation and the Upper Charles River Reservation, and fall within a number of communities in the greater Boston metropolitan area. The Charles River parks extend from the Charles River Dam, where the Charles empties into Boston Harbor, to Riverdale Park in the West Roxbury neighborhood of Boston. Most of the roadways within the parks are listed on the National Register of Historic Places as a unit, although Storrow Drive and Memorial Drive are listed as part of the Charles River Basin Historic District.
Document 6: Boston: Boston Common, located near the Financial District and Beacon Hill, is the oldest public park in the United States. Along with the adjacent Boston Public Garden, it is part of the Emerald Necklace, a string of parks designed by Frederick Law Olmsted to encircle the city. The Emerald Necklace includes Jamaica Pond, Boston's largest body of freshwater, and Franklin Park, the city's largest park and home of the Franklin Park Zoo. Another major park is the Esplanade, located along the banks of the Charles River. The Hatch Shell, an outdoor concert venue, is located adjacent to the Charles River Esplanade. Other parks are scattered throughout the city, with the major parks and beaches located near Castle Island; in Charlestown; and along the Dorchester, South Boston, and East Boston shorelines.
Document 7: The Crimson Patch: The Crimson Patch, first published in 1936, is a detective story by Phoebe Atwood Taylor which features her series detective Asey Mayo, the "Codfish Sherlock". This novel is a mystery of the type known as a whodunnit.
Document 8: Cold Steal: Cold Steal is a novel that was published in 1939 by Phoebe Atwood Taylor writing as Alice Tilton. It is the third of the eight Leonidas Witherall mysteries.
Document 9: Figure Away: Figure Away, first published in 1937, is a detective story by Phoebe Atwood Taylor which features her series detective Asey Mayo, the "Codfish Sherlock". This novel is a mystery of the type known as a whodunnit.
Document 10: The Adventures of Leonidas Witherall: Based on the novels of Phoebe Atwood Taylor (writing as Alice Tilton), the 30-minute dramas were produced by Roger Bower and starred Walter Hampden as Leonidas Witherall, a New England boys' school instructor in Dalton, Massachusetts, a fictional Boston suburb. Witherall, who resembled William Shakespeare, is an amateur detective and the accomplished author of the "popular Lieutenant Hazeltine stories."
Document 11: Boston: Boston is surrounded by the "Greater Boston" region and is contiguously bordered by the cities and towns of Winthrop, Revere, Chelsea, Everett, Somerville, Cambridge, Newton, Brookline, Needham, Dedham, Canton, Milton, and Quincy. The Charles River separates Boston from Watertown and the majority of Cambridge, and the mass of Boston from its own Charlestown neighborhood. To the east lie Boston Harbor and the Boston Harbor Islands National Recreation Area (which includes part of the city's territory, specifically Calf Island, Gallops Island, Great Brewster Island, Green Island, Little Brewster Island, Little Calf Island, Long Island, Lovells Island, Middle Brewster Island, Nixes Mate, Outer Brewster Island, Rainsford Island, Shag Rocks, Spectacle Island, The Graves, and Thompson Island). The Neponset River forms the boundary between Boston's southern neighborhoods and the city of Quincy and the town of Milton. The Mystic River separates Charlestown from Chelsea and Everett, and Chelsea Creek and Boston Harbor separate East Boston from Boston proper.
Document 12: Sandbar Sinister: Sandbar Sinister, first published in 1934, is a detective story by Phoebe Atwood Taylor which features her series detective Asey Mayo, the "Codfish Sherlock". This novel is a mystery of the type known as a whodunnit.
Document 13: Boston: Boston is surrounded by the "Greater Boston" region and is contiguously bordered by the cities and towns of Winthrop, Revere, Chelsea, Everett, Somerville, Cambridge, Watertown, Newton, Brookline, Needham, Dedham, Canton, Milton, and Quincy. The Charles River separates Boston from Watertown and the majority of Cambridge, and the mass of Boston from its own Charlestown neighborhood. To the east lie Boston Harbor and the Boston Harbor Islands National Recreation Area (which includes part of the city's territory, specifically Calf Island, Gallops Island, Great Brewster Island, Green Island, Little Brewster Island, Little Calf Island, Long Island, Lovells Island, Middle Brewster Island, Nixes Mate, Outer Brewster Island, Rainsford Island, Shag Rocks, Spectacle Island, The Graves, and Thompson Island). The Neponset River forms the boundary between Boston's southern neighborhoods and the city of Quincy and the town of Milton. The Mystic River separates Charlestown from Chelsea and Everett, and Chelsea Creek and Boston Harbor separate East Boston from Downtown, the North End, and the Seaport.
Document 14: The Cut Direct: The Cut Direct is a novel that was published in 1938 by Phoebe Atwood Taylor writing as Alice Tilton. It is the second of the eight Leonidas Witherall mysteries.
Document 15: The Hollow Chest: The Hollow Chest is a novel that was published in 1941 by Phoebe Atwood Taylor writing as Alice Tilton. It is the fifth of the eight Leonidas Witherall mysteries.
ground_truth: Mystic River
sub_queries: Sandbar Sinister >> author Answer: Phoebe Atwood Taylor
Phoebe Atwood Taylor >> place of birth Answer: Boston
Which is the body of water by Boston ? Answer: Mystic River