Marcel Heße (or Marcel Hesse) is a 19-year-old man who killed his 9-year-old neighbor and his 22-year-old friend in the German town of Herne.
On March 6th, 2017, Marcel lured his 9-year old neighbor Jaden into his apartment and stabbed him various times with a kitchen knife. He then sent numerous pictures of the dead body and voice messages to a friend, claiming that he just killed the neighbor's son and told them how he felt by doing so. For him it was nothing special. The friend posted some of these on 4chan not knowing how to react properly.
At 20.30 that day, Jaden's stepfather and older brother broke into Marcel's apartment, where they found Jaden's body and informed the police. Marcel then went missing.
Over the next days, various attempts to trace Marcel failed.
On March 9th, Marcel surrendered voluntarily in a snack bar, claiming that he just killed his 22-year-old friend Christopher and set his home on fire. The police then arrested him. The fire fighters found the half-burned corpse of Christopher, who had been stabbed 68 times in the chest.
Marcel told the police that he killed his neighbor in anger, because he was declined by the Bundeswehr, the German army. He actually tried to kill himself twice but both attempts failed, so he thought that the best thing for him would be to get imprisoned by killing someone.
He killed Christopher because he wanted to call the police after Marcel hid in his apartment for a couple of days.