Monday marks one month since former Japanese Prime Minister Abe Shinzo was shot dead while delivering an election campaign speech in the western city of Nara.

Investigative sources say police will examine the structure of a handmade gun seized from the scene of the shooting and other guns found at the home of the suspected shooter. They add that police will also test-fire the firearms to determine whether they are lethal.

Police arrested Yamagami Tetsuya, a 41-year-old unemployed resident of Nara City, at the scene of the shooting.

Police are investigating him on suspicion of murder. The suspect is currently undergoing psychiatric evaluation to establish whether he can be held criminally culpable.

Police say they have confiscated a handmade gun used in the shooting, which measures about 40 centimeters long and some 20 centimeters high. They say they have also impounded at least five homemade guns with a similar structure from the suspect's home.

Investigators quote Yamagami as saying he built a gun by taping together two steel pipes and also prepared more firearms -- a three-pipe type, a five-pipe type and a six-pipe type.

Police plan to pursue the case for suspected violations of the Firearms and Swords Control Law and the Ordnance Manufacturing Law.

Meanwhile, Nara City officials said that from July 10 through 15, their temporary hotline received 104 requests for consultation from people who complained of mental issues after the shooting.

Some people said they felt unwell watching TV news reports on the shooting. Others said they had been shocked that the incident occurred at a site they often passed.

City officials also launched an online counseling service at the start of this month.