TOKYO (THE YOMIURI SHIMBUN/ASIA NEWS NETWORK) - The suspect in the fatal shooting of former prime minister Shinzo Abe has said that the handmade gun used in the attack "was designed to fire six pellets at once", according to sources.

Several similar guns were found at the home of the suspect, Tetsuya Yamagami, 41, an unemployed former member of the Maritime Self-Defence Force.

The Nara prefectural police believe that Yamagami made several prototypes and selected the most lethal one to commit the crime.

Yamagami was arrested at the scene of the shooting on Friday (July 8).

Mr Abe, 67, was shot in the western city of Nara at 11.30am on Friday (10.30am in Singapore) and died in hospital later.

Mr Abe, who was Japan's longest-serving prime minister, had been campaigning for a Liberal Democratic Party candidate in the run-up to Sunday's Upper House election. He was making a speech near Yamato-Saidaiji train station when he was shot from behind.

The shooting shocked a country where guns are tightly controlled.

According to sources close to the investigation, a handmade gun seized at the scene was approximately 40cm by 20cm.

Yamagami has told the authorities that two metal tubes were bound together and secured with wooden boards and tape. The tubes contained a capsule that could hold up to six pellets, which would be discharged out of each tube in a single shot.

Based on video footage taken at the scene, Yamagami fired from a position 6m to 7m behind Mr Abe.

When the prefectural police examined a campaign vehicle at a road about 20m away from Mr Abe, they found multiple pellet holes in a signboard on the vehicle.

The prefectural police believe the holes were caused by stray pellets from the attack and, considering the distance, the pellets were emitted with great force.

The police searched Yamagami's home in Nara City on Friday and found several handmade guns similar in construction to the one used in the attack.

Each of the guns had several metal tubes bound together with tape, and one large gun had nine tubes bound together. They were also connected to an electrical cord that was believed to be used for ignition.

The police believe that Yamagami was making guns at his home and are investigating how he obtained the parts.

"I bought gunpowder on the Internet, got empty shell casings and filled them myself," Yamagami said. He also said that he "first tried to make a bomb, but it didn't work out, so I decided to make guns".

Nara prefectural police revealed on Sunday that Yamagami said he "test-fired (a homemade gun)".

Several wooden boards with multiple holes were found in his car, which was seized by the prefectural police, and he said that he used them for test-firing a gun.

The location of the test-firing is unknown, and the prefectural police are investigating the details.

On Sunday morning, the prefectural police sent Yamagami to the public prosecutor's office on a murder charge.