Diplomatic immunity is a long-standing legal principle that shields embassy and consular staff from prosecution or lawsuits in their host country.
In December 2018 police wrote to the New Zealand Security and Intelligence Service regarding Operation Brady and outlined complaints from Brady the case may be one of espionage: "She alleges burglary of her family home, her office, and unlawful interference with her vehicle. The complainant believes the Chinese Government is orchestrating these offences .... Any intelligence or information you may be able to provide would be appreciated."
The investigation apparently stalled in February 2019 - after a year of police work which also involved liaising with Interpol and Brady's office at the University of Canterbury being swept for bugs - with a declaration the case was "unresolved".
A summary of the investigation prepared when the case was put on ice and released to the Weekend Herald in 2020 noted: "Police retain some forensic samples that may lead to an identification in the future. Police has no evidence as to the identity of those responsible for the offences reported."
Key agencies and the Wellington embassy of the People's Republic of China declined to address questions about Operation Brady or whether diplomatic immunity was ever asserted.
Bin Zong, spokesperson for the Chinese Embassy in New Zealand, this week issued the first PRC comment on the case since Brady revealed details of the break-ins during testimony in February 2018 to the Australian Senate about foreign interference.
"The claims regarding the case are groundless and absurd, and the Embassy will not dignify such claims by any response," Bin said.
A spokesperson for police reiterated a statement first issued in February 2019 when they declared their probe had run out of leads to follow: "The investigation into Brady's claims remains open and is unresolved at this time. Police continue to assess information in the case. However, we will not be discussing specifics regarding the investigation."
A spokesperson for spy and security agency NZSIS said their agency on occasion supported police, but did not wish to elaborate on their involvement in Operation Brady. "The NZSIS has a long-standing approach of not commenting about specific operational issues or individual cases," the spokesperson said.
Former police officer Tim McKinnel said the inclusion of a diplomatic immunity briefing was "unusual" for a burglary case, and raised the possibility the investigation was considering the possibility suspects or persons of interest may be entitled to such protections.
"I don't think there's protection from an investigation being conducted, but it can make it difficult to advance an investigation to a prosecution," McKinnel said.
Brady told the Weekend Herald she was unable to add further information about the information released, but noted: "It is telling and significant that police were briefed on diplomatic immunity."
McKinnel said Operation Brady being left in limbo was likely to be unsatisfactory for all parties.
"Certainly from the victim's perspective, it's deeply unsettling. Brady is a pretty credible complainant, and you'd like to think that if anything that could have been done to resolve it has been done," he said.
"But because of the sensitive nature of issues related to diplomacy, it maybe be difficult for the police to disclose: It does leave Brady in a difficult position."
Brady herself described the burglaries as "shocking" and their purpose appeared to be intimidation, but was supportive of actions taken to date by police and NZSIS.
"No valuables were taken, including a large sum of cash and jewellery left out in plain sight. Only research-related items were taken, such as laptops and a burner phone," she said.
The Ombudsman's ruling on the Weekend Herald complaint about the failure to release more information largely sided with police. The Ombudsman cited provisions in the Official Information Act intended to protect the integrity of criminal investigation, and said police opposed releasing even the titles or descriptions of some documents.