A 28-year-old man was arrested Saturday on suspicion of sending an e-mail message to the Web site of Starbucks Coffee Japan, threatening to set fire to its stores on Sunday, Tokyo police said.

The suspect, identified as Hiroki Okano, reportedly told police he often frequented the chain's stores and was angry because shop staffers verbally abused him in a slanderous way. Investigators said they could not confirm any such conduct.

According to a police investigation, Okano accessed the chain's Web site from a personal computer at his home at around 8:15 p.m. Wednesday. He filled in a job application form with such phrases as "I'll set fire to all of your stores in (Tokyo's) Shibuya Ward on Christmas Day and kill all of your employees."

The message prompted staff at the stores to search for suspicious looking objects, obstructing normal business, according to police.