When a government seeks to extradite a fugitive, the case begins when prosecutors handling the prosecution in the United States send a request through diplomatic channels to the Department of State (L/LEI). The State Department conducts an initial review to determine (1) whether the requesting state has a treaty with the United States and (2) if the request appears to meet the requirements of that treaty. The State Department will also consider any written materials submitted to the Secretary of State by the fugitive, their attorney, or others and may ask for additional information from the requesting state.
Upon clearing this preliminary review, the State Department will transmit the request to its embassy in the country of refuge, which will formally present the request to the requested state authorities under a diplomatic note. The requesting state’s authorities then undertake their own review of the request, which usually involves a judicial phase in which a judge evaluates the facts and law in order to decide whether to extradite the fugitive.
During this phase, the requesting state will typically argue that there is probable cause that the person committed the alleged offense and that extradition should proceed. The requested state, however, may choose not to extradite the fugitive for various reasons. These might include that there is insufficient evidence to prove the alleged offense, or that the crime charged is not considered to be an offence under the laws of the requesting state. Alternatively, the requesting state may have an exception in its extradition treaty or in its national laws that it wishes to invoke.