Investigators in Japan have found what appear to be six bullet holes at a location where the man suspected of killing former Prime Minister Abe Shinzo says he tested a handmade gun.

The handmade firearm Yamagami Tetsuya allegedly used to fatally shoot Abe in Nara city, western Japan, on July 8 is believed to release six bullets at once.

Police say they found the bullet holes on Friday on the outer wall of a company building in the city.

The building lies adjacent to another housing the Family Federation for World Peace and Unification, previously known as the Unification Church.

Police say Yamagami had revealed that he test-fired a gun at a building of the organization at around 4 a.m. on July 7.

They say more than one local resident heard a gun-shot-like sound around that time. Police also say they found several bullet-like objects.

Abe was gunned down during an election campaign speech. Police are investigating Yamagami on suspicion of murder.