ICE requests Cook County sheriff to serve immigration subpoenas, threatens charges otherwiseICE sent a letter requesting Cook County Sheriff Tom Dart to serve immigration subpoenas, threatening criminal charges otherwise, records showed. ICE sent a letter requesting Cook County Sheriff Tom Dart to serve immigration subpoenas, threatening criminal charges otherwise, records showed. ICE sent a letter requesting Cook County Sheriff Tom Dart to serve immigration subpoenas, threatening criminal charges otherwise, records showed. ICE sent a letter requesting Cook County Sheriff Tom Dart to serve immigration subpoenas, threatening criminal charges otherwise, records showed. COOK COUNTY, Ill. (WLS) -- U.S. Immigration and Customs Enforcement is threatening to have Cook County Sheriff Tom Dart criminally charged.