"What occurred in the shop was completely unacceptable," said Anders Svensson, CEO of Ica Sweden, to Sveriges Television (SVT).
"He is guilty of something that we at Ica take a strong stand against, and we have informed him of this."
After the man caught the female shopper pinching items in his central Stockholm store, he rang the police and blocked the exit so the light-fingered customer was forced to wait with him for officers.
When the woman asked to use the store's bathroom, the staff member refused, at which point the shopper used a waste paper bin to relieve herself.
The shop assistant then poured the bin's contents back onto the woman.
During police interrogation, the staff member claimed that he was simply "giving back what belonged to the woman."
When the police arrested the woman, they asked her why her clothes were wet and she explained what had happened, although her story was denied by the shop attendant who claimed he had only poured dishwater on her.
However, the court refused to believe his claims and demanded he pay damages to the woman totalling 10,000 kronor ($1,540).