You must first find out wad's the person's IP address, after
which, you can check up the person's IP address at this
website:
http://www.completewhois.com/.
After the list of result had appeared, if the person's from
singapore and you know which ISP he is subscribed to, you can send
a report of abuse at the following website or email stated
below:
Starhub - [email protected] ( email add )
Singnet - http://www.singnet.com.sg/tou/misc/ia_incidentreport.asp
Pacific Internet - [email protected] ( email add )