Complex sentence: In turn, the State Migration Service of Ukraine confirmed Kolchenko's Ukrainian citizenship in February, and on March 27,2015, the Kyiv Prosecutor's Office opened a case regarding the abduction of an Ukrainian citizen Olexandr Kolchenko.
Split into simpler sentences: In turn, the State Migration Service of Ukraine confirmed Kolchenko's Ukrainian citizenship in February, and on March 27,2015. The Kyiv Prosecutor's Office opened a case regarding the abduction of an Ukrainian citizen Olexandr Kolchenko.