Ian Stewart: the narcissistic serial killer who fooled everyone

Ian Stewart, 61, who has been found guilty of the murder of his first wife, Diane Stewart, in 2010, six years before he went on to murder his fiancee, the author Helen Bailey. Photograph: Hertfordshire Police/PA

Ian Stewart’s ability to murder his first wife and resume a normal existence, going on to murder another partner, is beyond the comprehension of most.

The cold duplicity of his actions would lead many to ask how was he capable of such deceit.