 Complete the following phrase:  Leonard Petrosyan ; 13 October 1953  27 October 1999 is an Armenian politician who was the acting President of the Nagorno-Karabakh Republic from 20 March 1997 to 8 September 1997. He also served as Prime Minister of the Nagorno-Karabakh Republic from December 1994 to June 1998. He was killed in the 