HONG KONG — Walter Kwok, a Hong Kong property tycoon who was kidnapped and held for ransom in 1997 and later ousted, in a dramatic family conflict, from the business his father had founded, died on Saturday in Hong Kong. He was 68.

His wife, Wendy Kwok, confirmed his death in a statement but did not specify the cause. He had been hospitalized since August after having a stroke.

Mr. Kwok was one of Hong Kong’s most prominent developers when he was targeted by a mainland gangster who had an audacious plan to kidnap the city’s richest businessmen and ransom them for tens of millions of dollars.

The gangster, Cheung Tze-keung, known by the nickname Big Spender for his profligate ways in Macau casinos, kidnapped Mr. Kwok in September 1997, nearly three months after Hong Kong was returned to Chinese control.