A "very high-ranking police officer" who has since retired,  tipped off columnist Daphne Caruana Galizia that he had seen Energy Minister Konrad Mizzi in an intimate embrace with his communications coordinator Lindsey Gambin, a court was told today.

Ms Caruana Galizia testified before Magistrate Francesco Depasquale in a libel suit initiated against her by Ms Gambin about an article uploaded online in November last year.

Lawyer Andrew Sciberras, appearing for Ms Gambin, asked Ms Caruana Galizia whether she had verified that Ms Gambin was involved in an extramarital relationship with Dr Mizzi.

“These situations are very hard to verify,” Ms Caruana Galizia replied, mentioning the case of Labour MP Luciano Busuttil, who, she said, had created a fake Facebook account which he would use to woo women. She said the account was deleted moments after she confronted him about it. 

Her source, she continued, was a very senior police officer who had since taken early retirement, adding that she had no reason to doubt him.

He told her that he had seen them at the bar of the Tiffany Champagne and Cigar room at Portomaso, drinking champagne. It was at night, they are sitting next to each other and their body language was not that of a minister and his personal assistant.

They were also kissing, she said.

An AFM officer, the blogger continued, had also recently called her at midnight, saying that Dr Mizzi was at a Valletta bar "with a woman".

Suspecting her to be Ms Gambin, Ms Caruana Galizia said she sent her source a photo of the communications coordinator, asking if the woman drinking with Dr Mizzi was the same woman in the photo.

He said it was.

"If a married man is out drinking with a woman while his wife is abroad, he should be aware they are not invisible," she added.

She also said that some months ago, Dr Mizzi had attended a wedding of a One employee, accompanied by Ms Gambin.

“This is absolutely not professional behaviour," she said.