1) Human trickery.
2) Natural phenomenon, cause unknown.
3) Supernatural phenomenon of heavenly origin.
4) Supernatural phenomenon of diabolical origin.
This is true of every reported occurrence of weeping statues. I know of one or two instances which fall into category #1 and I know of several which I believe fall into category #3. As there are demonic counterfeits for many Divinely worked miracles, it wouldn't surprise me if there were some #4s floating around. This may be one.
***2) Natural phenomenon, cause unknown. ***
What was the temperature the days before the sweating began?
Wwhat was the temprature and HUMIDITY the day they noticed the sweating?
I have a workshop floor that sweats in humid weather and I have a house wall that sweated so bad the wallpaper fell off. The weather was extremely cold, then a warm humid front came through. The cold room was closed up and the warm humidity condensed on the wall.