Jari Seppo Aarnio (born 5 September 1957) is the former head of Helsinki's anti-drugs police. He has been sentenced to jail for drug crimes and other offences.
Aarnio spent 30 years in the anti-drugs force. He grew up in a suburb of Helsinki, and became a police officer in 1979. He was a chief investigator in a case against "drug baron" Miika Kortekallio in 1986. Kortekallio was sentenced to jail; Aarnio wrote his graduation essay about the Kortekallio league. He was named "policeman of the year" in 1987.
During 2011 and 2012, Aarnio abused his position by helping a gang smuggle and sell 800 kg of hashish into Finland. He also threatened a suspect, and tried to frame an innocent man for being in charge of the drug ring. He also used his position and experience to try to mislead his colleagues and to conceal evidence.
In 2017, Aarnio appealed to overturn his prison sentence. In July 2018, Aarnio was accused of murder, and was arrested for having allegedly failed to prevent a planned murder of which he had evidence in 2003.