Dozens of suspects linked to four extortion and usury rackets are to reappear before an investigating magistrate in Thessaloniki on Monday after being given more time to prepare.
Sources said the probe is to focus on the suicide last summer of a 45-year-old businessman who was unable to pay off huge debts to racket members.
Authorities are also to examine whether the suicides of other people with debts can be linked to the activities of the gangs, which are loosely connected.
Another businessman, who tipped off police about the racket leaders last May, was pivotal to the investigation. But it appears that the probe stalled following a leak regarding the police investigation. The leader of the biggest of the four rings was reportedly informed in July that a court order had been issued allowing authorities to access his bank account. The leak prompted the rackets to suspend their activities.