Kill it with fire. Not a single scrap must remain. Damnation aside, you simply can't predict what the effect of deaths will be nor that your information about your targets is accurate. While careful use might be able to improve the world no sane person should want so big a responsibility, and anyone who did would likely be just the sort of megalomaniac who shouldn't have it. The potential for abuse and tyranny is just too high.
As for whether you would get caught, I suspect you could probably manage it with convincing circumstances and infrequent times of death.
Another possibility would be to control people and have them give out information/resources, e.g. have a dictator give evidence of his contacts or a businessman give his fortune to charity.
Maybe I'm just shying away from the responsibility of making these decisions and wasting a great opportunity to improve the world, but I don't think I would trust myself or anyone else with this power.