Do you know which court tried the case? State or federal? If not, you might want to start your research by checking back issues of local newspapers to see if there are any articles that provide additional details.
Dear Sheron Adams,
Thank you for posting your request on History Hub!
We searched the National Archives Catalog and located the Inmate Case Files for 1895 through 1988 of several U.S. Penitentiaries in the Records of the Bureau of Prisons (Record Group 129) that may include a file for your grandfather. You may use the “search within this series” button so search for his name within each series. Some of these records have been digitized and may] be viewed online using the Catalog. For more information about any non-digitized records, please contact the National Archives (NARA) reference unit listed in that particular Catalog description (e.g. the National Archives at Atlanta (RE-AT) at firstname.lastname@example.org or the National Archives at Kansas City (RM-KC) at email@example.com).
Next, we located 9 series of criminal case files related to Mississippi in the 1940s in the Records of District Courts of the United States (Record Group 21) that may include a case file pertaining to your grandfather. For more information about these non-digitized case files, please contact the National Archives at Atlanta (RE-AT) at firstname.lastname@example.org.
Due to the continued impact of COVID-19, you may experience a delay in receiving an initial acknowledgment as well as a substantive response to your reference request from RE-AT, RM-KC, or other NARA reference unit. We apologize for this inconvenience and appreciate your understanding and patience as we balance mission-critical work and the safety of our staff during the pandemic. Please check NARA’s web page about COVID-19 updates for the latest information.
If your grandfather was charged in a state or local jurisdiction, then we suggest that you contact the County Offices of Marshall County, Mississippi, the Mississippi Supreme Court, or the Mississippi Department of Archives & History for further assistance.
We hope this is helpful. Best of luck with your family research!