Ulf Olsson (19 December 1951 – 10 January 2010), also known as Helénmannen ("the Helén man") was a Swedish murderer. He was convicted for the murders of 10-year-old Helén Nilsson and 26-year-old Jannica Ekblad in 1989. Found after a DNA test in 2004 (a test series including 28 other men), Olsson was convicted and sentenced to psychiatric care in 2005. Although he was first brought to the attention of the police in 2002, he had been in contact with two different police officers through anonymous letters and phone calls since only a couple of months after the murders.