SAYAMA, Saitama -- A man who shoved ice cream into a mailbox here has been arrested for violating the Mail Law, police said Saturday.

Yoshiaki Kobayashi, 42, admitted to the allegations. "I was frustrated because my job was not going well. I wanted to vent my anger," he was quoted as telling investigators.

Investigators are grilling Kobayashi over his alleged involvement in four other cases in which ice cream and liquid soap were poured into mailboxes near the scene and mail items were damaged.

In the specific case for which he was arrested, Kobayashi shoved chocolate ice cream into a mailbox in front of Shin-Sayama Station on the Seibu Shinjuku Line at around 7:30 p.m. on Friday, and dirtied mail inside it, local police said. (Mainichi)