Itaru Nakamura, Japan's police chief, announced his resignation on Thursday, saying he wanted to take responsibility for inadequate protection to former Prime Minister Shinzo Abe who was assassinated in broad daylight last month.
"As we push ahead with new security arrangements, it is natural to approach the matter with a new line-up of people," Nakamura told reporters here.
The 67-year-old former leader was shot in the back at close range by an ex-military man with a home-made gun during a campaign speech in the city of Nara on July 8.
The assassination shocked the country, known for its low crime rate and extremely strict gun laws.
The police chief resigned as he presented a report into the attack.
According to the report, an officer sent by the Tokyo Metropolitan Police as well as several local police officers were in the immediate vicinity of Abe on the day of the shooting.
Nevertheless, the perpetrator was able to approach Abe from behind unnoticed, pull his self-made weapon out of a shoulder bag, and fire two shots at the conservative politician.