As he rose through the ranks, Mr. Lee, who did not respond to interview requests, handled some of Hong Kong’s biggest criminal cases, including the pursuit of Cheung Tze-keung, a gangster known as “Big Spender” who kidnapped and ransomed members of the Hong Kong elite in the 1990s.
Officers from the police force’s organized crime bureau, which was then run by Mr. Lee, raided Mr. Cheung’s hide-out and confiscated 800 kilograms of explosives in 1998. The gangster escaped to mainland China, but was soon arrested and executed after a brief trial.
“As members of the gang were notoriously reckless and impulsive, we had to be extremely careful in planning and executing every detail of the operation,” Mr. Lee later recalled in a newsletter for Hong Kong’s Civil Service Bureau.
The success of his early career deepened Mr. Lee’s contacts within the mainland security services, leading to regular visits to police departments around China. That continued after he joined the leadership of the security bureau, which oversees the police.
In early 2019, he visited Xinjiang, the northwestern region of China where the authorities have carried out a brutal crackdown against Uyghurs and other predominately Muslim minority groups. Mr. Lee told lawmakers that the trip offered potential lessons for Hong Kong’s antiterrorism strategy.
The extradition proposal, which had been crafted by Mr. Lee, was made public that same year. In defending the bill, Mr. Lee said it would “block loopholes in the overall system of cooperation on criminal justice.” The city exploded in protests.