Fire investigators have narrowed down where Monday's blaze in Hamilton started, but just exactly what caused it remains unclear.
Mushroom clouds of black smoke could be seen from as far as Raglan early Monday as the fire ripped through AH Franks Tyres on Anglesea St - the second suspicious fire at the business in 24 hours, and the third since 2012.
The fire took nearly two days to fully extinguish due to firefighters not being able to access certain areas because of the unstable and fire-damaged southern wall.
![Asbestos removal workers at AH Franks Tyres on Tuesday. The worker on the right stands next to where Sunday's arson occurred, which is also near where Monday's fire started. Photo / Belinda Feek](https://www.nzherald.co.nz/resizer/v2/KH75TUH2D6ZRR7G6XITPBY2H7I.jpg?auth=862ef1fe547d9ac8c3ef98b4fedee4fdd4f99e798a517e2c6c976686662094b2&width=16&height=12&quality=70&smart=true)
Large amounts of asbestos left around the scene also had to be removed before investigators got inside yesterday.