The suspect in the assassination of former Japanese Prime Minister,  Shinzo Abe, identified as Tetsuya Yamagami,  believed the former Japanese leader was linked to a religious group he blamed for his mother’s financial ruin and spent months planning the attack with a homemade gun, police told local media on Saturday.

Tetsuya Yamagami, an unemployed 41-year-old, shot and killed Abe, 61 on Friday, July 8.

In videos of the killing shown on social media, he could be seen calmly approaching Japan’s longest-serving prime minister from behind and firing.

Sporting shaggy hair, the suspect was seen stepping into the road behind Abe, who was standing on a riser at an intersection, before unloading two shots from a 40-cm-long (16-inch) weapon wrapped with black tape. He was tackled by police at the scene.

Yamagami was a loner who did not reply when spoken to, neighbours have said. He believed Abe had promoted a religious group that his mother went bankrupt donating to, Kyodo news agency said, citing investigative sources.

“My mother got wrapped up in a religious group and I resented it,” Kyodo and other domestic media quoted him as telling police.

Media have not named the religious group he was reportedly upset with.

Yamagami jury-rigged the weapon from parts bought online, spending months plotting the attack, even attending other Abe campaign events, including one a day earlier some 200 km (miles) away, media said.

He had considered a bomb attack before opting for a gun, according to public broadcaster NHK.

The suspect told police he made guns by wrapping steel pipes together with tape, some of them with three, five or six pipes, with parts he bought online, NHK said.

Police found bullet holes in a sign attached to a campaign van near the site of the shooting and believe they were from Yamagami, police said on Saturday. Videos showed Abe turning toward the attacker after the first shot before crumpling to the ground after the second.

One of his neighbours, a 69-year-old woman who lived a floor below him, saw him three days before Abe’s assassination.

“I said hello but he ignored me. He was just looking down at the ground to the side not wearing a mask. He seemed nervous,” the woman, who gave only her surname Nakayama, told Reuters. “It was like I was invisible. He seemed like something was bothering him.”

Reuters also reported how a person named Tetsuya Yamagami served in the Maritime Self-Defence Force from 2002 to 2005, a spokesman for Japan’s navy said, declining to say whether this was the suspected killer, as media have reported.

This Yamagami joined a training unit in Sasebo, a major navy base in the southwest, and was assigned to a destroyer artillery section, the spokesperson said. He was later assigned to a training ship in Hiroshima.

“During their service, members of the Self-Defence Force train with live ammunition once a year. They also do breakdowns and maintenance of guns,” a senior navy officer told Reuters.

“But as they are following orders when they do it, it’s hard to believe they gain enough knowledge to be able make guns,” he said. Even army soldiers who serve “for a long time don’t know how to make guns”.