Jarno Sebastian Elg (born 1975) is a Finnish Satanist (portrayed as Devil worshipper by medias), who was sentenced to life in prison for murdering a 23-year-old man, eating some of the body parts and instigating others to participate in a ritual that included torturing the victim while listening to songs from The Cainian Chronicle album by the Norwegian black metal band Ancient on November 21, 1998, in Hyvinkää. Elg's partners were 17-year-old Terhi Johanna Tervashonka from Järvenpää, a 20-year-old man from Mäntsälä and a 16-year-old boy from Kerava.
Jarno Elg was tracked by the police and sentenced to life in prison. The Hyvinkää District Court in southern Finland sentenced accomplices Terhi Johanna Tervashonka, to eight years and six months in prison and Mika Kristian Riska, to two years and eight months. It was said that the three people "were strongly influenced by Satanism". The court declared most of the details of the case sealed for 40 years. For this reason, only a limited amount of information is available.
The criminal investigation started when a leg was found from a dump site, thus giving the name "dump site murder" to the case. The case was generally described as the most gruesome homicide in Finnish history.
After the sentences, the media "tried to raise up Black Metal as a scapegoat for the happenings in Hyvinkää". Demonos Sova of Barathrum "tried his very best not to involve Black Metal and Satanism with the murder" and called the murderers "some nutcases", whereas the I Return to Darkness fanzine "fully supports the murder of Hyvinkää and would like to hail in honour all those who participated in it". An article printed by the Norwegian Slayer fanzine stated that "[i]t's amazing how Satanists are always so full of strength and never forget to remind us that the week must be weeded out., yet when someone does actually weed out some weak hypocrite - thy are the first to mourn in public to save their precious Satanism from the terrible Devil Worshippers who ruin the whole name and essence of Satan which actions that, of course, don't have anything to do with 'real' Satanism", and told Sova to "[f]uck off and die". The article also questions why some people within the scene were "so fucking protective concerning Black Metal's 'good reputation'" although "Black Metal was the only form of 'music' where the music itself doesn't come as the first priority", whereas musicians now would seem to "care more about their guitars than the actual essence onto which the whole concept was and is based upon". In Metalion: The Slayer Mag Diaries, the fanzine's author Metalion stated that it was a "stupid article" and people gave him "lots of shit for printing the article, especially because the point of view tended to support the attackers".
In an interview given in 2000, Tervashonka explained that the case was not murder in her opinion. She said that a totally drunken group had tied and silenced their member who had become noisy by using a duct tape without understanding that he would die of suffocation as a consequence. After they found that the person was dead they had cut the corpse (while still being totally drunken) and also afterwards for the purpose of hiding it. Tervashonka denied that the case had been related to devil worshiping.
The Helsinki Court of Appeal granted Elg a parole in December 2014.