A person calling himself Satoshi Kirishima denies involvement in the incident, but suggests involvement in another incident. When investigators asked him what he thought about the series of incidents, he reportedly said he "regrets it." The Metropolitan Police Department is speeding up DNA testing and is currently analyzing what was heard.
The man was a member of the "East Asia Anti-Japanese Armed Front" wanted for his involvement in one of the serial corporate bombings that occurred in the 1970s. He was accused of being involved in the April 1975 bombing in Ginza, Tokyo.