Imagine my surprise this morning when I saw an incredible claim circulating that researchers from the Johns Hopkins University Bloomberg School of Public Health had conducted a study of fatal mass shootings in the United States but had “omitted one of the most often cited mass shootings in U.S. history.”

As it turns out, this claim actually was in-credible, as in, not credible.

I don’t read Breitbart so I don’t know if this error represents a legitimate mistake or a pattern of Kellyanne Conway-esque “alternative facts.” But I learned of the Breitbart article through another blog I follow, so I do know the error is already reverberating through the pro-gun echo chamber online.