Investigators have blamed a long-term propane leak inside a concrete wall for the explosion that killed five women at a biscuit factory in central Greece, leading to the arrest of three senior company officials.
The Arson Crimes Directorate (DAEE) discovered a perforated pipe embedded in the structure of the Violanta facility.
Officials concluded that gas had seeped into the surrounding soil and masonry over an extended period, creating a silent accumulation in the basement that ignited early Monday.
On Tuesday, police arrested the factory owner, safety manager, and shift supervisor.
They face charges of negligent homicide, causing grievous bodily harm, and arson through negligence.
The findings appear to validate earlier reports from staff who described a persistent smell of gas before the disaster.
"The gas saturated the building materials," an official said, explaining how the intact external tanks fed the leak deep within the factory's foundation.
The three suspects are scheduled to appear before a prosecutor today, Wednesday, as labor unions demand answers regarding the alleged oversight of safety warnings.