A man who set fire to his wife on a rural Waikato roadside before fleeing to Fiji has been sentenced to life in prison with a non-parole period of 14 years and six months for her murder.

Brad Callaghan's fiancee is standing by him, although their son will be a teenager by the time the convicted murderer is freed from prison. Tanith Butler gave birth to a son days after Callaghan, 33, was arrested in 2010.

The head of the Carmen Thomas murder investigation has criticised close friends of her killer