The precursor of the 1969 race riots can be traced to the 13 May Incident in Kuala Lumpur and Petaling Jaya in Malaysia.
People also talked indignantly about the partiality of the Malaysian Armed Forces in dealing with those suspected of involvement in the rioting; Chinese that were caught were severely punished on the spot and these rumours aggravated tension in Singapore.
Sino-Malay tensions surfaced again in Singapore in 1969 following the outbreak of the 1969 racial riots in Malaysia after the general election.
Many incidents of Sino-Malay clashes erupted and the situation was brought under control following security sweeps by the police and armed forces throughout Singapore.
[4] In April 1987, four silat (martial arts) experts were arrested by the ISD for actively spreading rumours of impending racial clashes on or around 13 May 1987 (on the 18th anniversary of the May 1969 race riots in Singapore and Malaysia).