Earlier this year, I caught a colleague stealing printer cartridges. We sat down together and discussed the matter and it emerged that this was just the tip of the iceberg. I suggested the colleague seek help and privately hoped that this person would resign in shame. This has not happened. What is more, a handbag has recently been taken. It seems odd to report the cartridges misdemeanour now, but who is to say that the thefts are not linked and will not continue? I am not sure what to do.

I think you did the right thing at first but got bamboozled by a devious mind. If nothing links the missing handbag to this person there is little you can do. I’d bring the matter up again with the person in question. If you are not convinced that the thefts have stopped, report them.