If you worked in Singapore for 6 months or more from age 16, you definitely need a Police Clearance for your US Embassy Interview.
Here's the instructions on how you get obtain a Singapore Police Clearance.
Certificate of Clearance (COC) is issued by the Criminal Investigation Department of Singapore Police Force to CITIZENS OF SINGAPORE to certify that a person has no criminal conviction in Singapore. Applicant must show documentary proof from the relevant consulate/immigration authority/government authority which clearly indicates that the production of the COC is required. All applicants must pay attention to the following application procedure and documentation requirements:
1) Singapore Citizen residing in Singapore is to appear in person at the COC Office located at Blk D Police Cantonment Complex, #02-07/08, 391 New Bridge Road, Singapore 088762. The office is open from 8.30am to 12.30pm, Monday to Friday (excluding public holidays).
2) Singapore Citizen residing overseas should submit their completed application forms (original) addressed to: Head Criminal Records, CID (COC), Blk D Police Cantonment Complex, #02-07/08, 391 New Bridge Road, Singapore 088762
3) Processing time for each application is about 10 working days.
4) Processing fee is S$45.00 per application. Payment can be made by cash, NETS, cash card, or credit cards (VISA/MASTERCARD) for walk-in application. Application sent by post (from overseas) must be accompanied by a bank draft made payable to ‘Head Criminal Records CID’ through a financial institution based in Singapore. In addition to the processing fee, a postage fee of S$5.00 must be included in the payment (total S$50.00) if the COC is to be sent to an overseas address. Payment is non- refundable once the application is processed.
5) Applicant with local address is to collect the certificate in person or via proxy.
6) All applicants must complete the Certificate of Clearance application form in full and submit it with the necessary supporting documents:
a) A set of applicant’s fingerprint impressions (ten prints). Applicants applying in person will be fingerprinted at COC office at the time of application. For application by post from overseas, the applicant must submit a set of his/her fingerprint impressions taken by a qualified Fingerprint Officer at an authorized office of the country he/she is now residing.
b) A photocopy of applicant’s valid passport. (Bio page only)
c) Two recent passport-sized photographs.
d) Photocopy of document from relevant consulate/immigration authority/government bodies to establish that the certificate is required by such authority. All documents are to be translated to English if written in other languages.
You can get the COC Form by clicking this link: www.spf.gov.sg