The president of the Criminal Bar Association says the police are right to re-interview Arthur Allan Thomas and his family as part of a review of the Crewe murder mystery.
Mr Thomas was convicted of the murders of Jeanette and Harvey Crewe, who were shot in Pukekawa in 1970, but was pardoned in 1979.
His family have accused the police of bias and harassment after they re-interviewed Mr Thomas as well as his two brothers, his sister and her husband.
Criminal Bar Association President Tony Bouchier says he is sympathetic towards the family, given they have had to live with the case for 40 years.
However, he says it is a reasonable step for the police to speak to people connected with the case.
He says it is understandable the family want a more independent review given the original case involved officers planting evidence, but the family should not judge the review before its findings are released.
Investigative journalist Pat Booth, who wrote a book about the original investigation, says the decision to begin a review does not make sense.
He says he is astounded the police are asking about alibis so many years after the incident.
Mr Booth says it beggars belief to ask people at this stage where they were on a particular night.