[anigbrowl]

That'd be nice, but sadly it's not the world we live in. Arson committed by firefighters is a small but expensive problem for the people who run fire departments. http://www.usfa.dhs.gov/downloads/pdf/publications/tr-141.pd...

Doctors are supposed to be moral paragons too, but every so often one is revealed to be abusing their trust in some horrific fashion.

[gaius]

Were these not part-time volunteer firefighters?

[anigbrowl]

Not necessarily, no. See for example p9, which documents two famous cases involving full-time professionals. Good screening practices seem to help a lot, but as you know perfect security is an unattainable goal.