The civil case centred around a 15-year-old who was suing Mr Frew for breach of privacy, following comments on Facebook linked to anti-social behaviour in the Ballymena area.
The girl, who cannot be named, was 14 when she was named on Facebook by Mr Frew earlier this year.
The girl sought damages from Mr Frew for breach of the statutory tort of harassment and for the misuse of private information.
But declaring that the girl had failed to establish liability against Mr Frew, District Judge Gilpin said the MLA “had acted throughout in good faith in making considerable attempts to address the issue of anti-social behaviour”.
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He said he was satisfied that Mr Frew had “thought rationally about the impugned posts” and had formed the view that to publish them was for the “purpose of preventing and detecting crime”.
Mr Frew said: “The court case since it begun in March has been an unsettling time, as I was made to feel like a criminal for simply standing up for the community I serve.
“I would like to thank all those who supported me during this time, not least my family.”