A homemade bomb, a gas cylinder, what was the big bang?
Everyone seems to have their own theory about the Waikato's "big bang", from exploding gas cylinders to homemade bombs.
Residents near the Taitua Arboretum were first to contact the Waikato Times with news of the noise, which happened about 7.30pm on Wednesday night.
But according to feedback, the blast echoed far and wide around Whatawhata. Without conclusive proof of the cause, theories abound.
Janice Fischer heard that the noise came from a burnoff of a pile of rubbish in Bowman Rd.
A hole had been filled with rubbish over a period of years, she said.
"They didn't realise . . . there was a gas cylinder at the bottom of the hole. Luckily no-one was killed."
Facebook user and Koromatua resident Lucy McCandlish commented to say the blast shook her house.
"Pretty scary. Heaps of concerned neighbours phoned the police and apparently it was a bunch of teens who lit a fire and chucked a homemade bomb in! Idiots."
According to Crystal Van Vliet's comment, something "exploded unexpectedly" during a Bowman Rd bonfire.
Senior Sergeant Pete Simpson said police had not been called to investigate the blast but assured residents it was not related to a P-lab. The fire service had no record of calls to the area on the night.
But readers from far and wide reported feeling or hearing the blast, including Natalie Mist in Te Pahu - about 10 kilometres from Whatawhata.
"If it was a homemade bomb, it must have been a mighty big one," she commented.
Ed Bronax lives south of Temple View and experienced a "terrible bang" which startled horses outside. And Alison Mackrell, who lives west of Whatawhata, thought a possum might have fallen on her roof - or perhaps there had been an "aeroplane toilet drop".