Ernst August Wagner (22 September 1874 – 27 April 1938) was a German mass murderer who, on 4 September 1913 killed his wife and four children in Degerloch.
He subsequently drove to Mühlhausen an der Enz where he set several fires and shot 20 people, of whom at least nine died, before he was beaten unconscious by furious villagers and left for dead.
He was the first person in Württemberg to be found not guilty by reason of insanity after several psychiatric assessments diagnosed him to suffer from paranoia.
He was brought to an asylum in Winnenthal, where later he wrote several plays and dramas.