Photo/Illutration Police officers cordon off the entrance to Yokohama Rubber Co.'s Mishima plant in Shizuoka Prefecture on Dec. 26. (Takahiro Takizawa)

MISHIMA, Shizuoka Prefecture—Police have arrested a former employee in connection with a rampage on Dec. 26 here at a tire plant in which at least eight workers were stabbed and others injured after being doused with a chemical liquid. 

According to the Mishima Police Station, Masaki Oyama, 38, was arrested on suspicion of attempted murder for stabbing a 28-year-old employee of Yokohama Rubber Co.’s Mishima plant on the plant grounds at around 4 p.m.

Investigative sources said that Oyama told police that he had been bullied when he worked at the plant.

The sources added that he used a survival knife to stab at least eight employees and wore a gas mask and used a sprayer to dispense chlorine bleach on other workers.

According to the local fire department that dispatched rescue workers, a total of 15 employees between ages 20 and 60 were injured in various parts of the plant and taken to hospitals. While five may have incurred serious injuries, no one was unconscious.

Other plant employees grabbed Oyama and held him until police arrived to arrest him. Police also found the knife used in the attack at the scene.

Local police believe Oyama acted alone and are looking into the motive for his attack.

Oyama lived in an apartment located about 350 meters from the plant. On Dec. 27, police searched the apartment with Oyama present.

According to Yokohama Rubber’s website, the Mishima plant manufactures automobile tires and had 987 employees as of December 2024.

A company spokesperson said prayers were extended for the full and early recovery of all the employees injured. The company will fully cooperate with the investigation, the official said.

A worker at a retail outlet near the plant said a number of police cars entered the grounds shortly before 5 p.m. A Yokohama Rubber employee who walked home from the plant said a suspicious character had stabbed a number of workers.

A 27-year-old woman working at a nearby restaurant saw a number of ambulances enter the plant site. The restaurant was within an area cordoned off by police, and the employee expressed concerns about whether the restaurant could open for business as usual.

A female employee in her 50s at an auto sales company located about 150 meters from the plant also expressed surprise at the large number of police cars and ambulances that drove around the area.

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