Bombing materials throw in residential but Polis refuse to come check

3-4 young adults throw in bombing materials into residential area during midnight. Loud explosion heard scaring everyone in and around the house. 999 was called but transfered to Sentul Police station. After 1 hour of reporting the case in varies call, finally the polis asked impatiently, "Are those kids chinese ?" After answered the young adults were most probably 'darker skin' persons. The polis still didn't show up 3 hours later at 3am.