A 43-year-old army warrant officer was arrested in Thessaloniki on Tuesday on suspicion of trying to swindle elderly residents.
Police said the suspect and an accomplice, who was being sought, phoned elderly people and convinced them that a loved one had been rushed to hospital for emergency surgery.
They told their victims that they needed to provide cash or valuables for the operation to take place.
The 43-year-old would collect the money, police said.
The pair are thought to have tricked seven elderly people on Monday alone.