<p>The <strong>Smiley face murder theory</strong> (variations include <strong>Smiley face murders</strong>, <strong>Smiley face killings</strong>, <strong>Smiley face gang</strong>, and others) is a theory advanced by retired <a href="https://en.wikipedia.org/wiki/New_York_City" title="New York City">New York City</a> <a href="https://en.wikipedia.org/wiki/Detectives" title="Detectives">detectives</a> Kevin Gannon and Anthony Duarte, and Dr. Lee Gilbertson, a criminal justice professor and <a href="https://en.wikipedia.org/wiki/Gang" title="Gang">gang expert</a> at <a href="https://en.wikipedia.org/wiki/St._Cloud_State_University" title="St. Cloud State University">St. Cloud State University</a>.<a href="https://en.wikipedia.org/wiki/Smiley_face_murder_theory#cite_note-1">[1]</a> They allege that a number of young men found dead in bodies of water across several <a href="https://en.wikipedia.org/wiki/Midwestern_United_States" title="Midwestern United States">Midwestern American states</a> from the late 1990s to the 2010s<a href="https://en.wikipedia.org/wiki/Smiley_face_murder_theory#cite_note-2">[2]</a> did not accidentally <a href="https://en.wikipedia.org/wiki/Drowning" title="Drowning">drown</a>, as concluded by <a href="https://en.wikipedia.org/wiki/Police" title="Police">law enforcement agencies</a>, but were victims of a <a href="https://en.wikipedia.org/wiki/Serial_killer" title="Serial killer">serial killer</a> or killers.</p> <p>The term "smiley face" became connected to the alleged murders when it was made public that the police had discovered <a href="https://en.wikipedia.org/wiki/Graffiti" title="Graffiti">graffiti</a> depicting a <a href="https://en.wikipedia.org/wiki/Smiley" title="Smiley">smiley</a> face near locations where they think the killer dumped the bodies in at least a dozen of the cases. Gannon wrote a <a href="https://en.wikipedia.org/wiki/Case_study" title="Case study">textbook case study</a> on the subject titled "Case Studies in Drowning Forensics".<a href="https://en.wikipedia.org/wiki/Smiley_face_murder_theory#cite_note-3">[3]</a><a href="https://en.wikipedia.org/wiki/Smiley_face_murder_theory#cite_note-auto-4">[4]</a> The response of law enforcement investigators and other experts has been largely skeptical.</p>