Though the police here have released little information about Gavin Long, a deeper portrait is beginning to emerge, based on a large trail left online.
Many of these digital breadcrumbs — web posts, YouTube videos and podcasts — are tied to Mr. Long’s given name, or some version of a new name, Cosmo Ausar Setepenra, which he filed court documents in Missouri to adopt in May 2015.
There is evidence that he sought to do the right thing, pursuing higher education and serving his nation. There is also evidence of paranoid thinking, and an interest in shedding blood to advance the cause of oppressed peoples.
In an interview with a podcast host in March, Mr. Long identified himself as a member of the online community of so-called targeted individuals, people who believe they are being harassed with mind-control weapons and by armies of stalkers.