A massive manhunt was under way in Sarawak after a gang of 30 Indonesians and Sarawak communists attacked a police station and nearby homes, killing nine people, including two policemen.
Troops and police teams were mobilised to try to block off the attackers' escape routes, and military reinforcements were on standby in Singapore as well to help in Sarawak.
The murders sparked fears that communists in Sarawak had joined forces with the Indonesians, along the lines of the Malayan Emergency, a guerilla war waged from 1948 to 1960 by the Malayan Communist Party against British rule in Malaya.
Indonesia appeared to be trying out the terror tactics used by the communists during the Malayan Emergency, said Sarawak Deputy Chief Minister James Wong.
"We expected such a thing to happen long ago because every time the Indonesians came across, they returned with bloody noses. They have got to show some success," he said.
In the June 27 raid at the police station and villages around the 18th-mile Kuching-Serian Road, masked attackers also seriously injured two policemen and took all the ammunition from the station.
The attacks were vicious.
A villager was having his bath in his shop when he heard pounding on the door, The Straits Times reported. He rushed out to open the door, only to be shot in the face.
Another man was clubbed to death, and one was hanged.
Witnesses said they heard sorrowful pleas for mercy before bursts of gunfire.
One of the dead policemen was Sergeant Simon Peter Ningkan, the 35-year-old brother of Sarawak Chief Minister Stephen Kalong Ningkan.
Leaflets bearing a message from the Chief Minister, promising retribution against the perpetrators, were air-dropped throughout the area.
Investigations showed that local communists played a bigger-than-expected role in helping the Indonesians that day.
The Sarawak Chinese Association condemned the brutal attack and urged people to take a stand.
"If the people fall into the trap by becoming fearful and silent, if they waver in their determination to stand firmly against the common enemy, then the enemy will surely step up his campaign," it said in a statement.
It is not known whether the perpetrators were ever caught.