In 1862, John S Shipman advertised in the Brooklyn Standard Union that his services included "pictures taken of deceased persons" as well as "views made of private dwellings."
How might I gather evidence to test the claim that this was the same man as Second Lieut. John Shipman of F Company, Second Regiment Scott Life-Guard reported as "leav[ing] for East New-York to-day and [...] going into encampment there" in the New York Times of 20 May 1861?