The Pana Wave Laboratory group in Fukui, five of whose members were arrested Friday on suspicion of beating an associate professor of a Fukuoka university who died in the group's facility in August, compiled a manual giving instructions on how to administer punishment beatings to members, police said Friday.
The police are questioning the members to determine whether the group as a whole was involved in the fatal assault on Satoshi Chigusa, 40, an assistant professor at Fukuoka University of Education.
Manabu Fujimori, 42, and four other members allegedly beat Chigusa repeatedly with bamboo swords and sticks. The blows left him with injuries to the back and waist.
According to the police, the manual instructed the number of strokes to administer as well as the items to use to beat people.
After examining Chigusa's injuries, the police suspect that the members beat him severely and repeatedly based on the manual.
The police also found that there was a hierarchy in the group, and Fujimori and the other suspects played various roles, with some ordering beatings and others carrying them out.
The police will investigate who compiled the manual and also probe the structure of the group and whether punishment beatings were routine.