A mob boss was shot to death Saturday night in a parking lot used by his yakuza group in Oizumi, Gunma Prefecture.
The incident appears to be related to a gang war, police said Sunday.
The police identified the victim as Takao Nishida, 59, who was head of Nishida-gumi, affiliated with the Sumiyoshi-kai crime syndicate.
The shooting took place around 9:50 p.m. Saturday in an area near shops and homes, police said.
A female passerby said she heard several shots, and a man believed to be the shooter fled the scene in a car parked nearby, they added.
Nishida took most of the bullets in the head. He was taken to a nearby hospital, where he was confirmed dead soon after arrival, according to the police. The incident is being investigated as a murder connected to feuding between rival gangs.
Police said they are probing for possible links between the murder and a series of shootings between Sumiyoshi-kai and Yamaguchi-gumi in neighboring Tochigi Prefecture.
The two groups are among the major underworld syndicates in Japan.