Police have attempted to lift fingerprints from alarm boxes at an Auckland apartment building engulfed in fire on Sunday to try to establish who turned the system off.
The alarms were not working in the two-storey building on Commerce St from which four people were rescued, including two men who climbed onto the roof to escape the blaze.
Detective Sergeant Scott Hunter said detectives had spent about seven hours at the scene along with Fire Service investigators to try and establish what happened.
"Crime officers were down fingerprinting the alarm boxes to see if we could actually identify or lift any fingerprints in regard to who may have turned the audible alarms off," he said.
The building's manager, Jonathan Kim, has previously said the alarm was checked monthly.
"We've got some inquiries to do around who checked the alarms and what their reports said," Mr Hunter said.
Auckland area fire commander Kerry Gregory said it was "almost unbelievable" that no-one died in the fire.
He said switching off alarms was "completely unacceptable". Early warning systems were critical for occupants who had "very little time to escape".
Anyone in a building who knew of an alarm that had been deliberately silenced should notify the owner or the Fire Service immediately, Mr Gregory said.
"People who live in these buildings and those who have responsibility for the alarms, need to heed the lesson from this weekend's fire."
Fire investigators earlier said the blaze started in an apartment that should have been locked.