On 21 January 1946, the Chinese War Victims Relief Association (CWVRA) held a memorial service at the execution site as a second anniversary of the massacre.
The park grounds and marble memorial were built in 1948 at the behest of the West Coast Memorial Fund Residential Committee (WCMFRC).
At the same time, it was decided that the site of the massacre and its burial sites should be a permanent place of remembrance for all North Borneo's victims in World War II.
The inauguration of the memorial took place on the fourth anniversary of the massacre on 21 January 1948.
In 1949, the remains of the men who were murdered by the Japanese military police (kenpeitai) and interred in Labuan were reburied at Petagas.

The memorial continued to play an important role in North Borneo's historical consciousness even until the foundation of Malaysia in 1963 through the first Chief Minister Fuad Stephens and the Head of State Mustapha Harun, whose personal histories were closely linked with the resistance movement.
Jules Stephens as one of the members of the revolt serving under the North Borneo Volunteer Force (NBVF), was the father of Donald Stephens, while Mustapha was a member of the movement itself.
In 1979, the memorial was renovated by the Kota Kinabalu City Government with the financial support of the State Government and extended with a parking space and a public toilet.
The wooden monument was replaced with a marble stone.
During the renovations, several stone clay jars with human remains were discovered in the burial ground.
These turned out to be the ex-prisoners from the Labuan military prison which had been re-buried in Petagas.

Since the opening of the Petagas War Memorial site, an annual memorial service has been held on 21 January with the participation of high-ranking state politicians, families of the victims and the general population.
At the 1998 service, a representative of the Japanese government and the Japanese consul in Kota Kinabalu attended the ceremony for the first time.

On 21 January 2018, the annual commemoration included another eight civilians who were not part of the Albert Kwok group.
 Their names (Lothar Wong Manjaji, Vitalianus Joseph Lim @ Ubing, Simon Thien, Bung Ah Tee @ Stephen Pan Tet Liong, Paul Chong Pin Sin, Paul Lee Fook Onn @ Paul Lee Onn, Lim Hock Beng and Mohinder Singh a/l Harnam Singh Kalsi), were added onto a new plaque at the main monument.
Following the discovery of the War Crime Document WO235/884 of the 1946 Trial Proceedings (held in Changi Singapore), the families applied for and received an official acknowledgement from the Dewan Bandaraya Kota Kinabalu that between 12 June and early July 1945, a Japanese kempeitai had blacklisted the 8 civilians as detrimental elements supporting the allies and ordered them to be (unlawfully) killed.
The original Document is held at the National Archives in the United Kingdom.
A copy of that Document, certified by The National Archives is held at the Sabah Museum.
As the eight men were not guerilla members from the Albert Kwok group, their families requested for a separate memorial wall to be constructed also at the Petagas War Memorial garden.
 After a positive meeting with the Sabah State Secretary, who supported the request, a site at the garden was identified for the memorial construction.
The Sabah state government led by Deputy Chief Minister and State Tourism Minister Christina Liew also plans to convert the whole Memorial garden into a historical site and tourist attraction in the city of Kota Kinabalu.
In early 2020, a memorial hall to be built in the site of the war memorial.
On 21 January 1946, the Chinese War Victims Relief Association (CWVRA) held a memorial service at the execution site as a second anniversary of the massacre. The park grounds and marble memorial were built in 1948 at the behest of the West Coast Memorial Fund Residential Committee (WCMFRC). At the same time, it was decided that the site of the massacre and its burial sites should be a permanent place of remembrance for all North Borneo's victims in World War II. The inauguration of the memorial took place on the fourth anniversary of the massacre on 21 January 1948. In 1949, the remains of the men who were murdered by the Japanese military police (kenpeitai) and interred in Labuan were reburied at Petagas.
The memorial continued to play an important role in North Borneo's historical consciousness even until the foundation of Malaysia in 1963 through the first Chief Minister Fuad Stephens and the Head of State Mustapha Harun, whose personal histories were closely linked with the resistance movement. Jules Stephens as one of the members of the revolt serving under the North Borneo Volunteer Force (NBVF), was the father of Donald Stephens, while Mustapha was a member of the movement itself. In 1979, the memorial was renovated by the Kota Kinabalu City Government with the financial support of the State Government and extended with a parking space and a public toilet. The wooden monument was replaced with a marble stone. During the renovations, several stone clay jars with human remains were discovered in the burial ground. These turned out to be the ex-prisoners from the Labuan military prison which had been re-buried in Petagas. 
Since the opening of the Petagas War Memorial site, an annual memorial service has been held on 21 January with the participation of high-ranking state politicians, families of the victims and the general population. At the 1998 service, a representative of the Japanese government and the Japanese consul in Kota Kinabalu attended the ceremony for the first time.
On 21 January 2018, the annual commemoration included another eight civilians who were not part of the Albert Kwok group.  Their names (Lothar Wong Manjaji, Vitalianus Joseph Lim @ Ubing, Simon Thien, Bung Ah Tee @ Stephen Pan Tet Liong, Paul Chong Pin Sin, Paul Lee Fook Onn @ Paul Lee Onn, Lim Hock Beng and Mohinder Singh a/l Harnam Singh Kalsi), were added onto a new plaque at the main monument. Following the discovery of the War Crime Document WO235/884 of the 1946 Trial Proceedings (held in Changi Singapore), the families applied for and received an official acknowledgement from the Dewan Bandaraya Kota Kinabalu that between 12 June and early July 1945, a Japanese kempeitai had blacklisted the 8 civilians as detrimental elements supporting the allies and ordered them to be (unlawfully) killed. The original Document is held at the National Archives in the United Kingdom. A copy of that Document, certified by The National Archives is held at the Sabah Museum. As the eight men were not guerilla members from the Albert Kwok group, their families requested for a separate memorial wall to be constructed also at the Petagas War Memorial garden.  After a positive meeting with the Sabah State Secretary, who supported the request, a site at the garden was identified for the memorial construction. The Sabah state government led by Deputy Chief Minister and State Tourism Minister Christina Liew also plans to convert the whole Memorial garden into a historical site and tourist attraction in the city of Kota Kinabalu. In early 2020, a memorial hall to be built in the site of the war memorial.
Petagas War Memorial