According to the Yokohama District Court's ruling in June 2022, Ishibashi was enraged after being warned by Hagiyama about the way he had parked his car in an expressway parking area just before the incident. Ishibashi pursued Hagiyama, who was traveling with his 39-year-old wife Yuka and their two daughters. Ishibashi drove directly in front of Hagiyama's car four times and repeatedly engaged in obstructive driving by slowing down and approaching close to Hagiyama's vehicle. Hagiyama subsequently took the risky action of stopping the car on the highway before being rear-ended by the truck. The defendant was handed the 18-year sentence at his first trial at the Yokohama District Court in December 2018. After an appeal, the Tokyo High Court in 2019 upheld the decision but quashed the ruling and sent the case back on a technicality, citing an illegal procedure by the lower court.