Police are hunting an arsonist who likes to burn buses in Wellington.
For the second time in six months a Wellington depot has been targeted and the damage bill is in the millions.
Last night two Go Wellington buses were destroyed and a third badly damaged after being set ablaze at the Karori depot.
Witness Blaise Orsman said he heard some loud cracking and popping and within two minutes at least two buses were well alight.
"They went up really quickly...within five minutes, big fireballs," Mr Orsman said.
The Fire Service has been praised for getting there quickly and dousing the blaze and their experts, along with police, are now examining the scene for clues.
"We'll continue to work through some of the forensic evidence we've uplifted and hopefully we'll establish something that will give us some leads to bring this guy to justice, arrest someone and give the community some reassurance," Detective Sergeant Mike Sears said.
The culprit is targeting vehicles well back from the road and the bus company says more vehicles could easily have been damaged.
"Very frustrating, especially as we reviewed security after the last one and had a security guard on site," chief operating manager Rachel Drew said.
In November three buses were destroyed and two damaged by an arsonist at the same depot. The offender has never been caught.
Go Wellington says there will be no disruption to the public and it is increasing security along with police who will patrol the area as well.