An investigation has found no evidence to support allegations that police officers coerced a woman into confessing to crimes in the late 1990s.
The Independent Police Conduct Authority investigation examined claims surrounding Joyce Conwell's convictions for the attempted murder of Doreen Middlemiss and the fatal shooting of Alec Rodgers.
In 2011, Joyce Conwell's sister Denise Lane complained to the Ombudsman, who then referred the matter to the IPCA.
The authority's chair, Judge Sir David Carruthers, said there was no evidence that the confession was extracted under duress.
However, Sir David found that it was undesirable for a detective senior sergeant to escort Ms Conwell from Dunedin to Christchurch by himself and noted a failure by police to make further inquiries to corroborate some of her statements.