Police have revealed a six-digit code unlocked crucial evidence in the death of Christchurch real estate agent, Yanfei Bao

A jury's found Tingjun Cao guilty of murdering Bao, after luring her to a property viewing in July last year.

Her body was found in a shallow grave at a Greenpark farm, just over a year later.

Detective Inspector Nicola Reeves says the breakthrough came from an investigator, who guessed Bao's phone code correctly with two attempts remaining.

It ultimately filled in the blanks of the investigation.

Reeves says it was one piece of a big puzzle - and is acknowledging members of the community, who provided invaluable information throughout the investigation.