Japanese police believe the suspect who shot former Prime Minister Abe Shinzo deliberately picked out a gun that was highly lethal for the task.

Abe was fatally shot as he was making a campaign speech on Friday morning near a railway station in the western city of Nara.

The shooter approached Abe from behind and fired two shots.

Police later found a small hole in a board fixed to the top of a campaign vehicle that was parked about 20 meters from where Abe was standing.

They believe the hole may have been made when part of a bullet pierced the board.

The suspect, 41-year-old Yamagami Tetsuya, was arrested on the spot. Yamagami is an unemployed resident of Nara.

The gun that was used in the shooting is believed to have been made with two pipes wrapped together with tape.

Yamagami told investigators that in addition to making a gun with two pipes, he also made guns with up to six pipes.

Police believe this shows Yamagami was intentionally trying to make a firearm that was as deadly as possible.

Yamagami told police he held a grudge against a specific religious organization and believed Abe was connected to it.