These are only some of the resources available.
Students may want to visit town clerks in search of Stonington and East Haddam land records.
Venture Smith-Making Freedom by 
Making Freedom by 
Venture Smith and the Business of Slavery and Freedom by
LIBGUIDES: "Reconstructs the journey of an eighteenth-century African from enslavement through emancipation"
Five Black Lives by
LIBGUIDES: "Five Black Lives is a collection of ex-slave narratives which spans 150 years in time, from 1729 to 1870, and some thousands of miles in geographical area from Africa to Connecticut. The autobiographies include the lives of Venture Smith, a native of Africa who ended his days as a resident of East Haddam, Connecticut; James Mars, born a slave near Norfolk, Connecticut in 1790, and freed at twenty-five by state law; William Grimes, a native of Virginia, who became Connecticut's first known runway when he arrived in New Haven about 1808; G.W. Offley, from Maryland, who was bought free by his father and later settled in Hartford; and James L. Smith, of Virginia birth, who escaped from slavery and settled in Norwich, Connecticut."--Victor B. Howard, The New England Quarterly
African American Connecticut Explored by
LIBGUIDES: "Winner of the Connecticut League of Historic Organization Award of Merit (2015) The numerous essays by many of the state's leading historians in African American Connecticut Explored document an array of subjects beginning from the earliest years of the state's colonization around 1630 and continuing well into the 20th century. The voice of Connecticut's African Americans rings clear through topics such as the Black Governors of Connecticut, nationally prominent black abolitionists like the reverends Amos Beman and James Pennington, the African American community's response to the Amistad trial, the letters of Joseph O. Cross of the 29th Regiment of Colored Volunteers in the Civil War, and the Civil Rights work of baseball great Jackie Robinson (a twenty-year resident of Stamford), to name a few. Insightful introductions to each section explore broader issues faced by the state's African American residents as they struggled for full rights as citizens. This book represents the collaborative effort of Connecticut Explored and the Amistad Center for Art & Culture, with support from the State Historic Preservation Office and Connecticut's Freedom Trail. It will be a valuable guide for anyone interested in this fascinating area of Connecticut's history. Contributors include Billie M. Anthony, Christopher Baker, Whitney Bayers, Barbara Beeching, Andra Chantim, Stacey K. Close, Jessica Colebrook, Christopher Collier, Hildegard Cummings, Barbara Donahue, Mary M. Donohue, Nancy Finlay, Jessica A. Gresko, Katherine J. Harris, Charles (Ben) Hawley, Peter Hinks, Graham Russell Gao Hodges, Eileen Hurst, Dawn Byron Hutchins, Carolyn B. Ivanoff, Joan Jacobs, Mark H. Jones, Joel Lang, Melonae' McLean, Wm. Frank Mitchell, Hilary Moss, Cora Murray, Elizabeth J. Normen, Elisabeth Petry, Cynthia Reik, Ann Y. Smith, John Wood Sweet, Charles A. Teale Sr., Barbara M. Tucker, Tamara Verrett, Liz Warner, David O. White, and Yohuru Williams."
These are a few suggestions.