Historical Scene Investigation is one of my favorite resources for U.S. History teachers and students. I've used it and referred people to it for years. HSI presents students with historical cases to "crack" through the use of evidence found in the form of primary source documents.
Historical Scene Investigation contains thirteen cases in which students analyze "clues" found in primary sources in order to form a conclusion to each investigation. For example, in the case of The Boston Massacre students have to decide if justice was served. HSI provides students with "case files" on which they record the evidence they find in the primary source documents and images they are provided. HSI provides templates for students to use to record observations from the evidence.
HSI is produced by College of William & Mary School of Education, University of Kentucky School of Education,
and the Library of Congress Teaching with Primary Sources Program. My video overview of HSI is embedded below.
As I mentioned in the video above, once you have done a couple of these with your students it becomes easy to craft your own HSI activities or have them craft HSI activities for each other to solve.
On a related note, Common Craft has a good video that explains the differences between primary and secondary sources. That video is embedded below.
Disclosure: I have an in-kind relationship with Common Craft.