Police were called to Morrisons in Chorley, Lancashire, after a supermarket worker allegedly slapped a four-year-old boy.
The staff member insisted the incident was a misunderstanding and police took no action.
However a furious message by the boy's mother, posted publicly to the Morrisons Facebook page, has since been viewed by over 300,000 fans.
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Selina Johnson said: "Today I had the worst experience any parent could have today one of your staff smacked my four-year-old’s legs.
"My poor little boy cried his heart out.
"I have complained to the store manager and called the police who will be taking a statement and we will be pressing charges.
"I will never set foot in on one of your stores again [sic]."
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A spokesman for Morrisons confirmed the incident had taken place and that police had attended the store after a complaint was made.
The spokesman said: "The member of staff in question has been suspended pending a disciplinary next week."
But he added that after discussions with all parties, police would not be pressing charges.
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A Lancashire Police spokesman said to The Mail Online: "It was reported to us but it was settled by community resolution.
"We spoke to all parties involved and everybody was happy with the outcome.
"The member of staff was spoken to and said she tapped a child in a friendly manner but realised afterwards this may have been misjudged.
"The family were more than happy with the outcome so there’s been no formal action on our part."