5.
It was widely reported after the Columbine shooting in 1999 that assailants Dylan Klebold and Eric Harris were members of the “Trench Coat Mafia,” a group of outcasts at Columbine high school who wore black trench coats. Immediately after the shooting, students fleeing the building reported that Klebold and Harris were members of this group, to the point where the New York Times reported that the dozens of members were potentially also responsible for the shooting. Today, we know that Klebold and Harris were never actual members of the group.
While the two sometimes wore black trenchcoats, students saw the two enter school on the day of the shooting wearing trench coats, which most likely led to the association.
In fact, most of the members of the “Trench Coat Mafia” had previously been seniors and had graduated the year before. As Columbine was a school that held over 2,000 students, many of them didn’t actually know Klebold or Harris personally.
Source: https://www.buzzfeed.com/mayaogolini/common-myths-we-all-believed