Claiming that he wanted to make more friends, an Immigration and Checkpoints Authority (ICA) inspector abused his position and performed multiple unauthorised checks on foreign women who had entered Singapore.

Yeo Kian Boon, 31, even called one of them and was caught after her Singaporean boyfriend complained to ICA about his antics.

Yeo, who is now employed as an administrative officer and is no longer working with ICA, was fined $29,000 yesterday after pleading guilty to six counts of performing such unauthorised checks and one count of abetting a colleague to do so. Sixteen other charges for similar offences were considered during sentencing.

Yeo, who used to be an ICA team leader at Changi Airport Terminal 1 (T1), had access to computer systems meant to be used only for work purposes. These include i-Borders@Central, which can be used to access information such as a person's travel history and passport details, and i-Borders@DO, which can be used to decide whether to grant or refuse entry to a traveller.

Yesterday, Deputy Public Prosecutor Alexander Woon said Yeo's job was to supervise the other ICA officers and deal with any persons whom they referred to him.

While on duty at the T1 Arrival Hall at around 8.50pm on Dec 12, 2015, Yeo screened a Thai woman and allowed her to enter Singapore. The next day, he added her on Line, a mobile communications app, and began calling her through it. However, she did not answer his calls, the court heard.

On Dec 22, she made a video call to him to ascertain the identity of the person trying to contact her. DPP Woon said she was surprised to learn he was the ICA officer who had cleared her to enter Singapore.

Yeo also contacted one of his then colleagues, Mr Lau Jia Yi, and asked him to dig up the woman's details. Mr Lau logged on to i-Borders@DO at the airport's Terminal 2, obtained the information and sent it to Yeo via WhatsApp.

While on duty at T1 on Dec 27 that year, Yeo accessed i-Borders @Central and i-Borders@DO to perform six unauthorised screenings on the Thai woman and other female travellers from Japan and South Korea.

The Thai woman told her boyfriend about Yeo's overtures and he complained to ICA about Yeo through an e-mail the next day.

Yeo's lawyers, Mr Josephus Tan and Mr Cory Wong from Invictus Law, said in their mitigation plea that their client's intentions were "naive and innocent".

The lawyers also told District Judge Jasvender Kaur that Mr Lau was given a warning in lieu of prosecution and has since resigned from ICA.

In response to queries, ICA told The Straits Times that its officers are expected to discharge their duties professionally and maintain a high standard of integrity. "We take a serious view of errant officers and those who break the law will be dealt with in a firm and fair manner, in accordance with the law."

It added that advisories on offences, such as the misuse of IT systems, are also issued to officers to reinforce the message that ICA has zero tolerance for such offences.