Dear Ms. Mooney,
Thank you for posting your request on History Hub!
We searched the National Archives Catalog and located three series -- Extracts from the Journal of the Board of Supervising Inspectors Relating to Regulations Approved After the Sinking of the General Slocum, 11/28/1904 - 3/20/1906; Index to Casualties Described in the Annual Reports, 1852 - 1911 and Annual Reports, 1895 - 1931 in the Records of the Bureau of Marine Inspection and Navigation (Record Group 41) that contain information about the investigation. These are records of the Steamboat Inspection Service in the Department of Commerce and Labor. For access to these series, please contact the National Archives at Washington, DC (RDT1) via email at firstname.lastname@example.org.
In addition, the Criminal Case Files, 1845 - 1988 mentioned in the exhibit titled Slocum Disaster, June 15, 1904 are in the custody of the National Archives at New York (RE-NY). Please contact RE-NY via email at email@example.com for access to the case file.
We hope this is helpful. Best of luck with your research!