In the three years of Mr Edmund Kwok's leadership, the National Kidney Foundation has seen its patient numbers grow by a third, to about 4,000.

It was also recognised for its good governance, receiving the Charity Council's Special Commendation for Risk Management Award and the Charity Transparency Award this year.

According to colleagues and patients who knew him, Mr Kwok had dedicated himself to the foundation since taking the helm of one of Singapore's biggest charities.

Staff described him as a caring boss who made himself accessible and available.

This was why NKF's announcement yesterday that he had been sacked came as a surprise. He is also now the subject of a police investigation for a "reportable offence" against a colleague.

Mr Kwok, who is married with two children in their mid-20s, could not be reached yesterday.

No one was at his terraced house in Hougang last night except his maid.

Mr Kwok is also an elder at the Zion Serangoon Bible Presbyterian Church. Its senior pastor, the Reverend Yap Kim Sin, told The Straits Times that the church is aware of what has happened.

"We are doing our best to support Edmund and his family through this difficult period."

NKF chairman Koh Poh Tiong described Mr Kwok as one of the best CEOs he had worked with.

One employee who declined to be named said: "He was a great CEO, he was always concerned about his staff. It is quite sad that he has to go because of this."

His subordinates had his mobile phone number and would text him to share their problems at work or at home.

He was also popular with patients. Mrs Lim Su Chin, mother of a nine-year-old former dialysis patient, was touched that Mr Kwok visited her daughter in hospital earlier this year. "She was getting a kidney transplant and he came over to encourage her. He is very friendly," said Mrs Lim, a housewife.

He regularly interacted with patients at the dialysis centres.

"He doesn't just stay in his office but comes down to talk to us and to understand the problems of patients," said Mr S. Shanmuganathan, a 52-year-old part-timer trainer with the National Cadet Corps, who goes to an NKF centre in Bukit Batok thrice a week.

Mr Kwok also drew attention for his looks. Mr Shanmuganathan said the first thing he noticed about Mr Kwok was his mohawk hairstyle.

"I didn't think it was an appropriate image for a CEO to portray to patients," he said.

However, others saw it as a quirk that complemented his lean physique and his keen interest in fitness.

Mr Kwok, who was with Parkway Healthcare as its vice-president of oncology before joining the NKF, cycles regularly and often pushed out sporting activities as a fund-raising platform and to encourage patients to adopt a healthy lifestyle.

Two years ago, he ran alongside a kidney patient in a 10km fund- raising race although he suffers from knee pain.

In three weeks, the NKF will hold a 30-hour stationary cycling challenge to raise money to subsidise the transport expenses of patients.