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Mr Pearce said it was hard to understand why anyone would commit such an act.
"It's incredibly disappointing and I encourage anyone with further information to come forward. This wasn't accidental."
Investigations are continuing with police to identify those responsible, he said.
"A number of exhibits are yet to be forensically examined. Once examined, we believe these will be helpful in providing identification evidence."
Anyone with information can contact Tauranga Police on 07 577 4300.