Families of the Pike River disaster victims are blasting police after an investigation was launched into whether Police were responsible for the second explosion.
Speaking to Newshub's national correspondent Paddy Gower, Pike River families' spokesman Bernie Monk said police "need to come out and be truthful to the country".
On Tuesday, Gower revealed an investigation is underway into whether a conveyor belt inside the mine was started up, which could have created a spark which ignited methane and ended all hope of finding any of the men inside alive.
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In rarely seen footage taken from down at the portal, a 'clunk' sound can be heard, which some say is the conveyor belt starting up. The belt can be seen starting to move before the mine explodes.
Official documents show authorities considered turning the belt on to give survivors a chance to ride it out, although they cautioned it was a "moderate risk" which could ignite a secondary explosion.
Mr Monk says families have been "neglected" throughout the whole process, police "did not do their investigation properly", and he's demanding someone be held responsible.
"There has been no one to investigate what has happened," says Mr Monk, who lost his son Michael in the mine.
"The country deserves to know the truth of what happened at Pike River and the police need to come out and be truthful to the country."
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Police told Newshub on Tuesday afternoon that based on their current knowledge, they have no information to suggest the belt was switched on after the first explosion.
They say mine experts have viewed the footage and concluded the movement of the belt was actually caused by the second explosion.
They also say a warning siren would have sounded if the belt was activated, but they have no report of that happening.
Dean Dunbar, who also lost his son in the disaster, told The AM Show on Wednesday he doesn't believe them.
"That will continue to be their defence, denial," he told host Duncan Garner.
"The police - from what the evidence says - went through the proper protocols, they did risk assessments, they reviewed risk assessments, they retyped risk assessments, and those signatures are on those risk assessments to run that tunnel belt. And they ran that tunnel belt," Mr Dunbar alleges.
"Unfortunately it looks like it caused the second explosion. We have our own experts that swear black and blue that that belt has been started up."