I am skeptical. Animal hairs as short as a mouses would burn off in seconds and would tend to smolder more than flame. I am smelling a rat here. The only one who witnessed this is the homeowner who is collecting the insurance.
...and his insurance company could easily deny the claim.
Rodent damage is a standard exclusion in most policies.
Well it was a conspiracy. The owner paid off the mouse to light the house on fire. The mouse got paid with a block of cheese.
I too am skeptical---It was either a VERY large mouse with fur like a sheepdog's or a mouse blessed with superintelligence that knew just where to run, and sat under flammable curtains as long as needed to set the house ablaze. And WHY coiuld the homeowner not have seen the fire start and go put it out?