Katariina Meri-Tuulia Pantila, born Katariina Hyttinen in 1981, pursued a career in nursing in Finland. She married and took the surname Lönnqvist during her first marriage. Following her divorce, she reverted to her maiden name and later remarried, adopting the surname Pantila. Details about her early life and motivations remain scarce in public records.

In March 2007, while attending a family gathering, Pantila administered an unauthorized insulin injection to an infant, leading to a medical emergency. Shortly thereafter, she poisoned a mentally disabled patient under her care, resulting in the patient's death. Authorities arrested Pantila, leading to her trial and subsequent conviction for the murder of the patient and the attempted murder of the infant.

Dubbed "The Angel of Death" by the media, Pantila was sentenced to life imprisonment in 2009. On March 8, 2010, she was found dead in her cell at Turku Prison, having died by suicide.