As the facts in the case become clearer, there is bewilderment and outrage that Cullen was able to kill for so long. Suspicions about his involvement in nursing home deaths were raised as long ago as 1993, but were never followed up. He drifted from hospital to hospital and former employers failed to pass on their misgivings despite his unusual behaviour.

"What I’m coming to understand is that, short of an actual conviction or revocation of a license, none of that information gets shared," said the chief medical officer at Somerset Medical Center, the last hospital where Cullen worked and where he may have killed up to 15 patients. "If anything good comes from this, it would be to reform the system where we’re prevented from telling one another what we know out of fear, quite frankly, of being sued."