It is unlikely that USCIS will search foreign criminal records. However, this depends on the specific action/petition being filed. For example, if a petitioner is applying for naturalization/citizenship, a FBI background check will be performed. It is unlikely that any foreign records will be searched (unless specifically asked for in the petition). However, if you are applying for a visa abroad, such as a visitor, fiance, or student, your foreign criminal records will be searched by the overseas consulate to determine your eligibility for a visa. This is not controlled by USCIS or Homeland Security, but rather by the U.S. Department of State. Further, investigations are done by the U.S. consulate in any given country.