Mass shooters that killed with homemade guns?

(If there's already a topic about this, post it here so I will ask to delete my topic.)

Are there some notable mass shooters that killed with their own homemade guns? A example I have is Liu Shibing:

A man suspected of having injured 18 people, including 16 children, in Wednesday's school shooting case, has been seized in Beijing, said police authorities in east China's Anhui Province.

Beijing police seized Liu Shibing Thursday afternoon, said a spokesman with the public security bureau in Guangde county.

Liu, 33, fired with six home-made guns at children doing morning exercises at Niutoushan Primary School of Liudong township in Guangde at 8:13 a.m. Wednesday, injuring 16 pupils. The schoolmaster, named Chen Yubin, was also hurt in the gun fire.

Liu fled the site after knocking down Chen Yongfeng, a villager who tried to stop him from shooting. Chen was installing cable TV transmission lines near the school when the accident occurred.

More than 200 policemen kept searching for the suspect in nearby villages and woods, until the news of his arrest came at 4:00 p.m. Thursday.

"We can rest assured at last," said a villager who declined to be named. School sources said classes are to resume soon.

By Friday morning, nine of the injured children have been discharged from hospital and the other seven are still being treated at Jiuba Hospital of Huzhou city in the neighboring Zhejiang Province.

Villagers said Liu is single and envies his peers who have children. He was once heard saying, "I have no kids of my own, so I would kill other people's kids."

The powder he used in shooting was what is used to make firecrackers.

Sources: Chinese mental patient attacks school, School shooting suspect seized in Beijing

John Zawahri made the AR-15 he used in his shooting.

Kevin Janson Neal also manufactured the pistols he used in his spree.

Even if he's not a mass shooter, he's still a mass murderer; Walter Seifert built the flamethrower and mace he used in his attack.

Though not homemade but David Sonboly bought a "reactivated" Glock from the darknet which was originally used as a theater prop.

Seong Byung-dae murdered a police officer and planned to murder more using a homemade muzzleloading gun, in total he carried 6 homemade guns. In another article about Seong and the problem of homemade guns in Korea, it mentions an incident in 2007 where a 47 year old man opened fire in a park with a homemade gun he made using wooden sticks and iron pipes he collected from a scrap yard, though doesn't say if he hurt anyone.
Valentin Doroshenko murdered 2 police officers and injured 4 in Ukraine using several homemade guns, unlike the others on this thread his were more complicated despite being built by him alone, including a submachine gun and 2 bullpup guns.
Khalid al-Mahmara and Muhammad Ahmad Moussa Mahmara committed a mass shooting together at a cafe in Tel Aviv using improvised submachine guns they bought. These guns are quite common in Palestine due to being cheap.
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Nathaniel Berhow used a homemade .45 caliber pistol in the Saugus High School Shooting where he killed 2 and injured 3 before killing himself.

Stephen Balliet used homemade guns in the 2019 Halle Shootings, killing 2 and injuring 2

Not sure if this counts either but, Bastian Bosse carried a zip gun into the school with him, but never used it and I'm not sure if the photos of it have been released.

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Wei Xiaojun murdered 7 people with this firearm before killing himself (Shiquan, February 16th, 2021)