What do you do if you know a friend of yours is a crook? You might not have any actual evidence, but you know it for sure, and you could easily gather the necessary evidence without putting yourself to much effort. You also know that the authorities are rather plodding and/or in league with them, and are unlikely to catch your friend. What to do?
Thankfully this is a dilemma which I suspect many readers (at least those safely ensconced in developed countries) have never faced, however, it will be far too familiar to anyone who has had a field posting in a developing country for any significant length of time. The friend will work for the government in one capacity or another, and after a while it will dawn on you that they must be quite corrupt in how they are carrying out the duties of their office.
The simple moral response is to turn your friend in, but that is not short of consequences. Outsiders meddling in this way is definitely not welcomed! You may not even be believed and nothing will come of your intervention – corrupt networks inside government are quite resilient to this kind of accusation. Regardless of the outcome you will almost certainly lose the trust of all the other officials you need to work with in order to do your work. And in governments where petty corruption is endemic, will the replacement be any more virtuous? Indeed your friend may well be your friend (as well as colleague) precisely because s/he is less grasping and obviously corrupt than other local officials. There may definitely be a case of better the devil you know!
Finally, if this is a relatively junior official, which is likely to be the case in a field posting, do they really deserve to carry can for the whole corrupt system? Most likely they will just be part of a bigger network. In one case I have come across we have even speculated (probably naïvely, but friends are friends) that our friend was trapped in his corruption; that if he failed to continue to cooperate he would simply be hung out to dry. Indeed that is often the unfortunate outcome of anti-corruption drives around here in which one or two junior officials are made scapegoats for a much deeper-embedded corrupt network.
So inevitably you find yourself turning a blind eye. Without the subject ever being discussed between you and your friend you work out where the red lines are; at which point would you feel unable to continue to ignore the corruption? If they cross that line you may still feel unable to do anything, but by pushing the boundaries in this way they would cease to be your friend, becoming an adversary to be contained so far as is possible.
This moral equivocation then gets even worse when you yourself get involved in some kind of improved governance (i.e. anti-corruption) project. It is almost impossible not to co-opt government in many such projects – donors always require us to work in partnership with government – and so you find yourself sharing a stage with the same corrupt officials you are effectively targeting. (Of course, until charged and proven guilty they are presumed innocent, so you can hardly object to their involvement!)
The best that can be hoped for: either the authorities eventually get their (wo)man, but then you lose your friend, or you hope to create the conditions under which your friend’s corruption becomes impossible to sustain, and they simply cease it because they have no alternative. But this is probably just pie in the sky dreaming. In the meantime we carry on in our extremely morally-grey ways, such are the contradictions of a life in tropical conservation and development, and another step on the way to SNAFUdom.