A 28-year-old mainland Chinese man pleaded guilty in the High Court on Wednesday to robbery and forcibly taking or detaining a person, with intent to sell him for ransom.

Defendant Yang Chao pleaded for leniency in the court, saying he was manipulated by two compatriots to rob and kidnap veteran Hong Kong architect Ma Kim-see. He expressed deep regret to the victims and vowed he would never come back to Hong Kong, Sing Pao reported.

The court heard earlier that Yang and two compatriots, all from Guizhou province in southwest China, only got to know each other in Shenzhen two weeks before the robbery took place last year.

On December 15 in 2016, the trio crossed the border illegally by climbing the wall in Sha Tau Kok and swam to Hong Kong.

Two days later at around 8pm, the trio wore masks and carried knives when they entered the second floor of Ma’s luxury house at Bella Vista in Silver Terrace Road in Sai Kung, the New Territories, Apple Daily reported.

They trussed up Ma, his wife and a 51-year-old Filipino helper and made off with about HK$87,000 (US$11,140) in cash and jewelry.

However, the trio was not satisfied with the amount. They locked the maid in the toilet and forced the couple to drive their car out to get more money.

Ma’s wife was forced to go to a jewelry shop in a shopping mall in Tseung Kwan O with Yang and buy jewelry worth HK$261,000 with her credit card and withdraw HK$20,000 from an ATM.

Meanwhile, Ma was held by the other two robbers in an underbrush on the roadside. The maid later managed to untie herself and called the police, who arrested Yang and saved the woman at a roadblock.

Yang was remanded in custody until he is sentenced on December 4.

His two colleagues were understood to have sneaked back to mainland China but were arrested in Guizhou, where they are due to face a trial, Sing Tao Daily reported.