I think its more of a assistance in investigations. Treaty Between the United States of America and Ukraine on Mutual Legal Assistance in Criminal Matters with Annex, signed at Kiev on July 22, 1998, and with an Exchange of Notes signed on September 30, 1999, which provides for its provisional application. 1998   https://www.congress.gov/treaty-document/106th-congress/16/document-text Because the US Embassy says no  https://ua.usembassy.gov/u-s-citizen-services/arrest-of-a-u-s-citizen/information-u-s-citizens-arrested-ukraine/ This page contains information about the Ukrainian criminal justice system.  Although believed to be generally accurate, neither the Department of State, its Diplomatic and Consular Missions, nor its employees accept any responsibility for the accuracy of the information contained herein.  U.S. citizens should not rely solely on this information, but should direct specific questions regarding Ukrainian criminal procedures to a qualified attorney licensed to practice law in Ukraine. We must emphasize that changes in the Criminal Code, the Code of Criminal Procedure, and the regulations of any specific jail or prison may substantially limit the rights and privileges afforded to a U.S. citizen incarcerated in Ukraine.  It is the job of the incarcerated U.S. citizen’s attorney to keep him/her abreast of any changes.  This page was prepared solely as a guide to assist U.S. citizents in understanding the laws and procedures governing the Ukrainian legal and penal systems.  In particular, please note the following: The judicial system and personal rights one enjoys in the United States do not apply abroad. A U.S. citizen or national is entitled to claim consular protection abroad, regardless of evidence of guilt, the nature of the alleged crime, or the status of the citizen. Actions that can be taken on the arrestee’s behalf by U.S. Consular Officers include provision of needed consular services such as Emergency Medical/Dietary Assistance (EMDA), or administration of a trust fund in a timely and efficient manner. All persons (excluding diplomats) staying in Ukraine (including transit zones at airports) permanently or temporarily are subject to Ukrainian laws.  They can be sued, tried and fined or sentenced in Ukrainian courts.  The Ukrainian government takes its laws and regulations very seriously, perhaps even more so when a foreigner is involved. Investigations can be conducted by the Ministry of Internal Affairs (MVS), the Security Service of Ukraine (SBU), prosecutor’s offices, military detachment chiefs, pri  ffa  son or jail wardens, customs authorities, the fire control administration, border guard authorities, ship captains (when an incident takes place on the high seas), polar station directors (if transportation between the polar station and local law enforcement institutions is not available), and the tax police. Ukraine and the United States do not have an extradition treaty.