The idea of offering "rewards" for information leading to the arrest of a criminal fugitive didn't really take off in Japan until the Lindsay Hawker murder case. In 2009, two years after the young English teacher was killed, the police offered a ¥10 million bounty for any leads, and five months later her killer was apprehended thanks to several tips. According to media reports the reward was divided among four persons. Previously, the prevailing wisdom was that offering monetary incentives to the public for helping police catch suspects was mercenary and thus unacceptable, but results are results, and the system now seems firmly in place after the recent series of arrests of suspects in the Aum Shinrikyo sarin gas attack of 1995.
The three remaining Aum fugitives have all been captured in the last six months, two of them since the National Police Agency increased the reward for useful information from ¥3 million to ¥10 million in February. There has been speculation that the increase was actually occasioned by the arrest of the first Aum suspect, Makoto Hirata, in December. The police subsequently intensified their search for the other two fugitives, which the public had every right to believe had previously been lax given the almost comical circumstances surrounding Hirata's surrender. However, old attitudes die hard, and the reward system is still in a state of evolution. For one thing, two terms are being used interchangeably, hoshokin and kenshokin, both of which also mean "prize." Perhaps the authorities can't decide because they feel the two words send the wrong message.
The Metropolitan Police Agency won't release the names of the informants who may receive the rewards, though the media has been busy trying to describe them. Information about the whereabouts of Naoko Kikuchi was received by the police the morning of June 3, and they arrested her later that day, though others have said they offered tips about Kikuchi much earlier. Apparently, someone, reportedly a neighbor, brought the tip to the police, though it's not clear if that person will receive a reward.