The two men were classmates and long-time friends before becoming employer and employee.
Police believe the two-year-old climbed up on his own before accidentally falling headfirst into the appliance.
According to her, the police were unable to find evidence that could implicate the alleged perpetrator.
The complainant also raised concerns that the driver may be a private-hire vehicle driver.
The 137-year-old Japanese law prohibits any person from challenging another to a duel.
Her grandson is now in remission and undergoing follow-up treatments.
A netizen claimed the customer was the first to verbally abuse the staff member.
The office worker had relied on the sugary drinks to cope with work stress.
Police are still working to determine the motives behind the man's erratic actions.
Netizens showed support, suggesting that the WP's outreach posts indicated internal unity.