“There has been no attempt by us to oust the chairman,” Sherman Kwek, chief executive officer of City Developments Ltd., said in a statement late Thursday referring to his father. “The chairman’s claim that there is an ‘attempted coup’ by the majority directors to consolidate control of CDL’s board is not only incorrect, it distracts from the nub of the issue.”

Sherman Kwek’s response escalates the feud that’s roiled the family after his father Kwek Leng Beng filed a lawsuit alleging his son and other directors were leading a boardroom coup and accused them of serious lapses in corporate governance.

In particular, the elder Kwek objected to the appointment of two directors who were added to the board this month without going through the typical nomination process, according to his statement this week.

The worsening tit-for-tat has plunged Singapore’s largest listed developer into crisis, sparking a rare succession battle in the city-state. Shares of the $3.4 billion firm, already suffering from a major drop in profits, remain suspended, and have been downgraded by firms including JPMorgan Chase & Co.

In his latest salvo, Sherman Kwek accused his father of being influenced by Catherine Wu, an adviser to the board of the firm’s hotel subsidiary whose conduct raises “a very serious issue of corporate governance.”

“She has been interfering in matters going well beyond her scope, and she wields and exercises enormous influence,” the son said. “Due to her long relationship with the chairman, efforts that were made to manage the situation were done sensitively, but to no avail.”

Wu couldn’t be reached for comment while representatives for the elder Kwek didn’t respond to a request for comment.

Wu, 65, has been a longtime aide to the patriarch. The former singer who studied at The Juilliard School in the U.S. told local Chinese newspaper Lianhe Zaobao that she met the elder Kwek in 1992 at a dinner party. She migrated to Singapore from Taiwan the same year. 

She was described as a personal assistant directly paid for by the elder Kwek and acted as his “eyes and ears” on the ground, according to a 2018 judgment at a U.K. employment tribunal. 

Wu was listed as chief of staff at CDL’s hotel unit in the U.K. from 2022 until her resignation in January 2024. Her current and former business interests include child care services, music schools and cybersecurity firms, according to corporate filings reviewed by Bloomberg. She’s also known as Wu Ingrid Gwan and Wu Gwan Ying.

Sherman Kwek said a majority of directors passed resolutions on Feb. 21 to terminate Wu’s advisory agreement and to affirm that she “has no power and authority” to influence the boards, management and staff of CDL and its hotel unit, to “restore proper corporate governance and accountability.”

The younger Kwek also accused his father of not presenting a “full picture” of recent court proceedings related to the dispute. The elder Kwek said in a statement Wednesday that the two new directors have undertaken not to exercise any powers until further notice of the court.

In fact, the majority of the board voluntarily offered to preserve the status quo until a full hearing, according to Sherman Kwek’s letter.

“The suggestion in the chairman’s second press statement that the minority directors succeeded in their application and that lapses of corporate governance at CDL and its subsidiaries have been halted is most unfortunate,” Sherman Kwek said.