Police dog Xtra and development dog Soldier had been kept inside an air-conditioned pod at the back of a specially designed vehicle as their handler attended a development day in southern Sydney on Thursday.
The officer left the dogs in the vehicle at 10.30am to attend a lecture 300m away, but when he returned to check on them two hours later the German shepherds were dead.
Police say no human error was involved in the death of two dogs inside a specially designed pod. (HANDOUT/NSW POLICE)
The handler was devastated by the incident, NSW Police Commissioner Karen Webb said on Friday.
"He had the very difficult task of going home yesterday afternoon to inform his wife and his two children about the passing of the two dogs because the two dogs ... reside with the family," she said.
"They are part of that family (and are) with the officer 24/7."
The police vehicle was being examined for any mechanical, technical or engineering problem that led to the tragic circumstances, Ms Webb said.
"There's no suggestion that this is human error," she said.
The car appeared to have been working correctly when the handler left and there had been other dogs kept in the same type of pod in other police cars at the time, Assistant Commissioner Stephen Hegarty said.
The vehicles were heavily modified to include cooling pods in the back for the dogs, with the "state of the art" features introduced in 2023, he said.
But at some point the air conditioning stopped working, triggering an alarm near the end of the lecture, Mr Hegarty added.
When the officers returned to check on the dogs' welfare, it was too late.
Police did not currently believe the car ran out of fuel.
"Those dogs can be (kept) in the rear of the car at night time for long periods of time so it's not unusual and (not) against any ... processes or training we've given the officers," Mr Hegarty said.
Greens MP Sue Higginson questioned police protocols for looking after the dogs, saying they were clearly not adequately supervised and that led to their deaths.
"If a member of the public were to leave an animal that they were responsible for inadequately supervised in a vehicle, they would be committing an act of cruelty - why do the NSW Police get a pass on this?" she said.
A Greens MP says police should be treated like everyone else over the death of the two dogs. (HANDOUT/NSW POLICE)
Xtra had been with NSW Police since 2018 and he was well-known in the Newcastle area as a "crook catcher".
Soldier was 15 months old and started work with the force in February 2024 for training and development.
"(The handlers) work with the dogs, live with the dogs, they train with the dogs," Mr Hegarty said.
"It's a cliché, but it's their partner and they work with them every day."
Police have made immediate changes while the investigation proceeds, including kennelling their dogs and increasing the intervals of inspections.
A memorial will be held for the dogs at a suitable time and they will join the police Wall of Remembrance.
