Located about 2km north of Thong Sala. Come here to file a report. You might be charged between 110B and 200B to file the report, which is for insurance and refusing to pay may lead to complications. If you are arrested you have the right to an embassy phone call; you don't have to accept the ‘interpreter’ you are offered.
If you have committed a serious offence, do not sign anything written only in Thai, or write on the document that you do not understand the language and are signing under duress.