A mainland Chinese PhD student earlier slapped with a HK$5,000 (US$643) fine for splashing semen onto a woman’s buttocks has left Hong Kong before prosecutors can apply for a stricter penalty.

Lai Changwei, 26, failed to appear at Thursday’s West Kowloon Court hearing after the Department of Justice sought to review his sentence on the basis it was manifestly inadequate.

Lai, who was pursuing a PhD in neuroscience at City University of Hong Kong on a full scholarship, pleaded guilty in August last year to a count of indecent assault for using a plastic pipette to squirt a milky liquid containing his semen onto the 22-year-old victim at the varsity’s Kowloon Tong campus on June 6 last year.

The defendant, married and living in neighbouring Shenzhen, had blamed what he called a “careless” act on academic stress.

Magistrate Li Chi-ho, in sentencing the accused in September last year, highlighted Lai’s guilty plea and his lack of physical contact with the woman in justifying a financial penalty in lieu of prison.

Lai had been in and out of Hong Kong on multiple occasions after prosecutors applied for a review three days after the sentence. The defendant last left the city on January 12 and has not returned since.