Of all the things that had gone missing from his home, it was the loss of a portable power bank that upset Changi Airport Group chairman Liew Mun Leong especially.

Mr Liew, 71, who was testifying in court on Thursday, said the power bank was given to him after he delivered a guest lecture at a French university several years ago.

He took the "uniquely designed" device with him back to his home in Chancery Lane but could not find it just a few days later, said Mr Liew on the ninth day of the trial of Indonesian maid Parti Liyani, who is accused of stealing from the home of her employer. "I was very upset," he told the court.

Parti, 44, who had worked for Mr Liew's family for eight years, faces four theft charges involving more than $50,000 worth of valuables, including a $25,000 Gerald Genta watch, two iPhones and a Gucci wallet.

The items were allegedly found in the three boxes that she had packed to be shipped to Indonesia after she was asked to leave in 2016.

Mr Liew told the court he had instructed his wife, Madam Ng Lai Peng, his son, Mr Karl Liew Kai Lung, and daughter-in-law, Ms Heather Lim Mei Ern, to terminate Parti's employment on Oct 28, 2016, while he was overseas.

He said he made the decision after many years of things going missing in the house. "I have, in my heart, suspected her (of stealing) for many years," he said.

When questioned by Parti's lawyer Anil Balchandani on why he had not acted earlier, Mr Liew said he had previously suggested terminating her employment to his wife, but Madam Ng told him it may not have been Parti who stole the items. "So I tolerated (it) for many years," he added.

A day after Parti left, Mr Liew returned home and was informed that the family's belongings had been found in the three sealed boxes. He then decided to file a police report to prevent Parti from returning to Singapore to "possibly steal from other families".

In April, Parti had told the court that some of the items that she had allegedly stolen had been salvaged from trash bags left behind by Mr Karl Liew after he moved out of his father's house to his own home in early 2016.

On Thursday, Mr Anil suggested that Mr Liew's family had actually discarded the items and "decided now that they want it back". Mr Liew disagreed.

Among the items allegedly discarded were Longchamp bags, which Mr Liew testified were very unlikely to have been thrown away.

He told the court he had bought the bags while travelling overseas, and though they were inexpensive, they are "very durable and useful" and he "cannot imagine that someone would throw them away".

The lawyer also suggested that Mr Liew had "trumped up" his police report with details such as his discovery of photos of Parti with other men.

He had also told the police that he was worried that the men might cause a nuisance or break into his home, said Mr Anil. Mr Liew vehemently objected, saying he "has no reason to fix anyone".

He added that he was only trying to fulfil his duty as a citizen by reporting a theft in his home.

The trial resumes today.