Okay guys, I got a friend who works as a stall assistant in Sim Lim Square, she says on December 15/16, she cannot remember the date, but she says she saw a dark African-American cameraman somewhere near Bugis MRT, trying to film, and and two Caucasians, asking for directions to find an ice-cream man. She pointed them to a nearby McDonalds, but one of them nodded their head, saying no. She is sure that it is an older man, the other might be a girl.
I also know a small girl who told me that she saw people with backpacks, at Marina Bay Area (Singapore Flyer?), but could be a tourist group.