 Ensio Koivunen

Ensio Kalevi Koivunen (June 23, 1930 – May 27, 2003) was a Finnish serial killer who poisoned three female hitchhikers using carbon monoxide in the summer of 1971, and thereby got the nickname Häkä-Enska ("Carbon monoxide-Enska").On July 11, 1971, 23-year-old Salme Helena Metsänikula (born January 28, 1948) disembarked a bus in Anjala "en route" from Helsinki to Turku.