A 65-year-old man was charged on Friday with illegal possession of ammunition as authorities sought his 67-year-old brother after 11,055 bullets and six guns were found at two apartments owned by the men.
Police also discovered other weapons, including a sword, at the properties in Holargos, northeastern Athens, and Petralona, southern Athens.
They raided the property in Holargos earlier in the week after a tip-off that ammunition was being stored there.
The 65-year-old retiree was arrested but police were not able to find his brother when they inspected the Petralona apartment.
Officers said the 67-year-old had been accused of antiquities smuggling in the past and they suspect he had been selling the ammunition.