When news broke of an alleged rape case near Woodlands Park private estate in Kranji last week, resident Sarah Thiam and her family started to send messages to one another on their mobile phones, with reminders not to go out alone.

"We are now on high alert. I was quite spooked, as it could also have happened to me," said Ms Thiam, 26, a programme manager who often jogs along the road where the incident occurred.