The Second Kira Case was a follow-up of the initial Kira case, from the original Death Note storyline. Despite records of the rules of the Death Note being readily available to law enforcement agents (though highly classified), this case was not considered any easier by those who participated in it.
The case began in 2025, fifteen years after the death of Kira, when the World Health Organization (WHO) noted a rise in heart attack victims, garnering the attention of Interpol. From records of the previous Kira case, there was reason to suspect a possible rise of a new Kira, though there was no clear motive at the time. However, the recorded victims were seemingly at random and were of varying backgrounds, and ICPO disregarded it as merely a health issue that the WHO should investigate on its own.
However, the recorded victims of cardiac arrest on part of WHO gradually rose over the months, and Interpol ordered an investigation into the matter. The organization was eventually able to connect the later victims for past criminal activities, both confirmed and suspected, but it was unable to create an investigation team to track down what they presumed to be a new Kira, since it would be deemed a violation of Interpol's constitution; since it forbade the organization to "undertake any intervention or activities of a political, military, religious or racial character." Since Kira's fall about fifteen years ago, there has been a growing cult of followers of the so-called Kiraism: enough to be officially classified as a religion. Being unable to legally rally the police forces of the world, Interpol instead made it clear that there may be a new Kira on the loose, and encouraged the police forces of the world to be on alert.
FBI Director Nathanael Weaver became convinced that there was a new Kira on the loose and began utilizing resources of his department in order to investigate the matter further. Although frustrated by the slow progress, Nathanael continued his efforts in uncovering the meaning behind this. He avoided contacting people involved in the first Kira Case, since the director believed that this new Kira would hunt them down if any suggestion of them being involved in any form gets leaked. What made matters more frustrating was that L refused to partake in the case, claiming disinterest in participating in the involvement of the case. L noted to his subordinates, in his reasoning, that this Kira was nothing like the Kira that first appeared and was an insult to the memory of the original Kira and L. However, with advice from Rester and Lidner, L agreed to not completely rule out future involvement in the case.