He was well-known for handling many high-profile cases in the 1990s, such as the Mona Fandey murder case, bringing down local gangster P. Kalimuthu (Bentong Kali), and helping to coordinate rescue efforts during the Highland Towers apartment collapse.
He was the District Police Chief in different places such as Batu Gajah, Grik, Klang and Georgetown (1964–1972).
Subsequently, he was promoted to Director of Internal Security and Public Order Department at the Bukit Aman Police Headquarters (August 1987–1989) and was later transferred as the Director of Criminal Investigation Department at the Bukit Aman Police Headquarters from 20 November 1989 to 1994.
He also conducted operations on the arrest of Bentong Kali or also known as P. Kalimutu, and his last position before his retirement from the security forces was Director-General of the Prisons Department (1994–1997).
Mohd Zaman Khan died at the National Heart Institute, Kuala Lumpur on 11 September 2021 and was buried at the Bukit Kiara Muslim Cemetery.