In this article, (Gift Link) a New York Times investigative reporter explains how he has cultivated a source that he knows is distributing illegal drugs that may be fatal.
He writes in part,
“It was a small-time operation, but one that illuminated a big point for our reporting: A single person, without cartel backing, can order and redistribute potent chemicals.
I wanted to verify his account with others. But I also had to make good on my commitment not to reveal his identity. So I compared the information he was giving me with reporting I’d done with dozens of experts and law enforcement officials who told me what they understood about this market. I also spoke to people in his circle of friends and associates.
All along, I was keenly aware that the drugs Chemical Analyst was selling can be fatal. I asked him about this — as I’d asked other dealers and suppliers — and he professed here to be a libertarian. As a human, I find it terrifying the drugs he sells could kill people. It was painful to watch him use drugs himself, and I often feared for his safety. But as a reporter, I have a responsibility to explain to the public what’s really happening on the drug frontier.”
This is different from most Ethics Quizzes here, because my position is set and unshakable. The reporter’s duty “to make good on [his] commitment not to reveal [the drug pusher’s] identity” must be subordinate to his duty to society as a citizen and responsible human being. Even lawyers are authorized to violate a clients’ confidentiality to prevent death or serious bodily injury to a third party. How many people should die so that the reporter can explain what’s happening on “the drug frontier?” My verdict: none.
The reporter says he’s talked to lawyers and other journalists as well as “experts” and law enforcement officials. I doubt that he has talked with any ethicists.
Your Ethics Alarms Ethics Quiz of the Day(that I have already told you my answer to..) is…
Ethics Alarms 
In my opinion; the reporter is morally obligated to “sic the police on this criminal”; in fact, if I understand the law correctly, if he doesn’t sic the police on this criminal knowing full well that the drugs he’s selling are potentially and likely to be fatal if used, then the reporter could be held legally responsible (at some level) for NOT reporting that this criminal is selling something to people that could very possibly kill them.
There is a moral duty to act and he can still print his story to inform the public.