The shooting in Las Vegas, where Stephen Paddock fired from the vantage point of the 32nd floor of a hotel, highlighted the challenges that law enforcement officers face when drawing up security measures for events that draw a large crowd (How the Las Vegas shooter foiled a well-drilled counter-terrorism plan; ST Online, Oct 6).

The worry now is copycats.

Since a terrorist drove a cargo truck into crowds celebrating Bastille Day in Nice, France, last year, vehicles have been used as killing machines in Berlin, London and Stockholm.

Now, law enforcement agencies will have to enlarge the security ring fence to ensure large crowds gathering in open spaces do not become easy prey for terrorists targeting them from heights.

I hope the local authorities are constantly reviewing security policies and measures, and leave no stone unturned in scenario planning.

Gabriel Cheng Kian Tiong