Nakai was born in 1941 and ran a telephone dating club business in Kobe. In a dispute with a competitor she directed accomplices to attack two outlets of the rival firm.
On March 2, 2000 Molotov cocktails were thrown into the premises. Four male customers died of burns and smoke inhalation.
She did not throw them herself. The prosecution's case, which the court accepted, was that she had ordered and paid for the attacks. The Kobe District Court sentenced her to life imprisonment on November 27, 2007, more than seven years after the deaths, the delay reflecting the length of the investigation into who had commissioned them.
This is a commercial arson with fatal consequences, not a serial killing, and the entry says so. It is in the archive because the roster carries it. The accessible sourcing is Kyodo News reporting of the verdict.