Female serial killers are rare, those who act on their own initiative rarer still, and those who are the the senior partner in any sort of murderous enterprise...how many of them can you name?
In a mere fortnight, Joanna Dennehy stabbed five victims in frenzied knife attacks. Incredibly, the last two survived. These latter were men she had chosen at random. Dennehy might rightly be called a spree killer as well as a serial killer; her partner Gary Stretch - who shares a name with a former world class boxer turned actor - was rightly described as her nodding dog.
After the first body was found there was never the slightest chance that Dennehy would get away with it. In the end, she decided not to try. Herein we see some archive footage and hear the resident psychobabblers try to explain her actions. We hear the stock phrases about personality disorders, but these are mere descriptions, not any kind of so-called mental illness. One of them settles for the obvious, indeed the only explanation: some people are just evil.