In Malay language, we call it the 'biawak'.
I came in the afternoon when the sun was shining brightly and stayed around for some time, long enough for me to grab my camera and capture this moment. Based on its stance in this picture, I guess it was looking for food, not its mum... "Crouching Biawak, Hidden Prey", lol.
Before long it disappeared into the drains. Its movement was very fast - like Dash in the movie Incredibles.