Police are investigating matters, including repeated burglaries, on a well-known Christchurch academic.
Professor Anne-Marie Brady reported several incidents which have occurred since late 2017 including a burglary at her home, two break-ins at her university office, damage to her vehicle, and a series of anonymous phone calls.
The professor's work uncovering the extent of Chinese political influence in New Zealand over the past 18 months has received international attention.
Police have taken these incidents very seriously and a lengthy, detailed and extensive investigation has been conducted, Detective Superintendent Stu Allsop-Smith said in a statement.
"This has involved all necessary police resources including detailed forensic analysis, interviews and expert advice."
"The burglaries and other matters reported remain unresolved at this time," Mr Allsop-Smith said.
Police said there were no other lines of inquiry to pursue in the investigation unless new information becomes available.
Any new information would be carefully assessed to determine what, if any evidential relevance it may have, Mr Allsop-Smith said.
"Police, in conjunction with Professor Brady’s employer, will continue to provide updated advice to Professor Brady including security advice if required, and maintain an active response plan," he said.
Professor Brady has been updated on the status of the police investigation.