The detention of a 19-year-old Singaporean student under the Internal Security Act, for having made plans to join the Islamic State in Iraq and Syria and carry out violent attacks here, is unnerving.
It is the latest revelation of the lure of terrorist groups even amid the peace and tolerance that mark life in Singapore.
The self-radicalised youth had planned to attack key facilities and even assassinate government leaders here if he were unable to travel to Syria.
Also troubling is the arrest of another teen Singaporean for investigations into the extent of his radicalisation.
The 19-year-old's case, like innumerable others worldwide, shows the insidious allure of online terrorist propaganda tailored to the vulnerability of youthful discontents.
They are seduced into accepting the use of a degree of violence, which they would not have contemplated in their everyday lives.
The aim is to destroy what they have been convinced to believe are the wicked ways of the secular world.
The wish to slay leaders - a pathological desire not usually associated with the criminal imagination in Singapore - is a commentary on the apocalyptic heights to which propaganda can raise a person once he has been deluded into believing that a non-confessional system is evil.
Evidently, it would require several social forces to come together to throw a protective cordon sanitaire around the young.
If self-radicalisation through the Internet is not to grow in Singaporeans, parents and other family elders must communicate with their children, using the visceral credibility of biological and emotional ties to resist the anonymous grip of extremists masquerading as the global Muslim community.
Religious and community leaders must engage dissenters frankly, addressing any unease or disquiet that they might have over their place in an inclusively secular society.
Non-Muslim Singaporeans would help their Muslim brethren by continuing to believe that protecting the nation from terror is a collective task in which people of all faiths oppose a minority of religious zealots.
In the same vein, friends and colleagues should be alert to signs of altered behaviour that could signify an inner turn to radicalism.
Fortuitously, what led the authorities to the 19-year-old was a person who had noticed the changes in him.
Unfortunately, others whom he had failed to sway to his "cause" did not alert the authorities. This is misplaced confidentiality.
To bring a misguided relative or friend to the attention of official agencies is not to fail the trust that he has placed in relationships.
Instead, it is to save him, along with others, from the consequences of a possibly monstrous misadventure generated by the delusional relationships of the virtual world.