Hugh Pickens writes writes: "Andrei Chikatilo, “The Butcher of Rostov,” was one of the most prolific serial killers in modern history committing at least 52 murders between 1978 and 1990 before he was caught, tried and executed. The pattern of his murders, though, was irregular with long periods of no activity, interrupted by several murders within a short period of time. Hoping to gain insight into serial killings to prevent similar murders, Mikhail Simkin and Vwani Roychowdhury at UCLA built a mathematical model of the time pattern of the activity of Chikatilo and found the distribution of the intervals between murders follows a power law with the exponent of 1.4. The basis of their analysis is the hypothesis that “similar to epileptic seizures, the psychotic affects, causing a serial killer to commit murder, arise from simultaneous firing of large number of neurons in the brain.” In modeling the behavior the authors didn't find that "the killer commits murder right at the moment when neural excitation reaches a certain threshold. He needs time to plan and prepare his crime” so they built delay into their model. The killings eventually have a sedative effect, pushing the neuronal activity below the “killing threshold” – which is why there are large intervals of time between groups of murders. "There is at least qualitative agreement between theory and observation (PDF)," conclude the authors. "Stats can’t tell you who the perp is, but they’re getting better and better at figuring out where and when the next crime might happen," writes criminal lawyer Nathaniel Burney adding that "catching a serial killer by focusing resources based on when and where he’s likely to strike next is a hell of a lot better than relying on the junk science of behavioral profiling.""