Four Ground Self-Defense Force members based at Camp Nerima in Tokyo have tested positive for marijuana, Defense Ministry officials said Friday.
The urine tests were conducted on all 2,000 or so soldiers at Camp Nerima after another GSDF member at the camp, aged 28, was arrested July 8 on suspicion of possessing 7 grams of marijuana.
The officials said the latest finding indicates marijuana use may be spreading among GSDF personnel at the camp.
The GSDF, together with police, are investigating the case and will later punish the four.
In a five-year period through fiscal 2008, 39 Self-Defense Forces members have been punished for drug offenses, the officials said.