The government says it won't investigate further whether the death of a New Zealand aid worker in Ukraine was a war crime, but experts say more could be done.
Andrew Bagshaw and Chris Parry were shot while evacuating civilians in the Soledar region of Ukraine a year ago.
Bagshaw's parents, Sue and Phil Bagshaw, say evidence points to the pair being shot by the Wagner Group, the Russian-controlled private military company.
Phil Bagshaw says he's spoken to a Ukrainian investigator who has 10,000 war crimes cases on his desk.
He's calling on the New Zealand and UK governments to send their own investigator to Kyiv.
“This is the responsibility of the New Zealand and UK government to investigate a war crime of a foreign national killed on foreign soil.”
Post-mortem results showed both aid workers died from gunshot wounds to the head, and other parts of the body.
Days after their death, pictures surfaced of both men's passports on the Wagner Group's Telegram channel.
Phil Bagshaw said there were more witnesses he could direct authorities to.
But in a statement to RNZ, the Ministry of Trade and Foreign Affairs said that while it condemned the killings of Bagshaw and Parry, it won't be investigating further.
“In the current situation the ICC [International Criminal Court] and Ukraine authorities are best placed to pursue any further investigation including obtaining evidence.
“For privacy reasons the Ministry of Foreign Affairs and trade will not provide further comment about this individual consular matter including with respect to the reported causes of Andrew’s death and engagement with his family.”
The UK Foreign and Commonwealth Office told RNZ it does not investigate war crimes and also said any further investigation is for Ukrainian authorities.
Under the Geneva Convention, intentionally killing a civilian in armed conflict is a war crime.
A UK coroner's ruling last month found Parry was fatally shot while undertaking aid work.
That differs from the initial official explanation of the men's deaths, that their car was hit by artillery shell.
International Relations Professor Robert Patman said New Zealand and the UK could work together to investigate the death and should send a signal that it won't turn the other cheek to war crimes.
“It’s very important, I think, that New Zealand walks the talk about upholding the rule of law, even at the time of war, and that is our official position so we need to be [as] active as we can to pursue this.”
Andrea Furger, a researcher in international criminal law and state co-operation at the University of Melbourne, said it was a standard practice for foreign law enforcement officials to travel to other countries to investigate crimes against their citizens.
Furger said this relied on the agreement of the country where the crime was committed.
Dr Marnie Lloyd, a specialist in the law of armed conflict at Victoria University of Wellington, said under international humanitarian law, countries have an obligation to help facilitate war crimes investigations, even if they did not occur in their territory.
Lloyd said if Ukrainian authorities agreed, New Zealand or UK law enforcement officials could help investigate the deaths on the ground as part of a broader ICC case against Wagner Group members.
“It's not only about punishing the person or deterring future war crimes, but it is about documenting and witnessing what has happened.”
The Ukrainian prosecutor's office said last year it was looking at 100,000 allegations of war crimes committed by Russia, with numbers rising weekly.
Investigators from Poland, Estonia, Lithuania, Slovakia, and Romania have gone to Ukraine to help work on the cases.
The International Criminal Court is also investigating.
Both the UK Foreign Office and MFAT said they have provided funding for the ICC's prosecutions in Ukraine.
Neither department responded to RNZ's questions about why the official explanation of the deaths differed from the post-mortem evidence.