Four people have been arrested on suspicion of stealing more than 30 bicycles for the purpose of exporting them to North Korea, police in the city of Hiroshima said Tuesday.

The four are company employee Yoshifumi Yamane, 30, Katsuyoshi Sasaki, a 45-year-old seaman, 63-year-old Tadao Kadooka and a 17-year-old youth. All are from Sakaiminato, Tottori Prefecture, police said.

Investigators said they suspect the thefts were systematic and that a group is arranging shipments of stolen bicycles to North Korea.

Police said the four suspects stole more than 30 bicycles from a municipal bicycle parking lot in Nishi Ward, Hiroshima, at around 7 a.m. Sunday. The bicycles had been collected by the city for disposal because they had been left unclaimed, police said.

A witness notified police, who arrived at the scene. The suspects initially tried to lie their way out, claiming they had received permission from the city to take the bicycles away, investigators said.

Yamane was quoted as telling investigators his company began collecting old bicycles starting around August.

According to local residents, the firm is a trading company that for the past month or so has had trucks loaded with some 40 to 50 bicycles parked in front of it every two or three days.