Generate a correct and concise answer for the question based on the words in the context.

Context : James Charles Kopp (born August 2, 1954) is an American citizen who was convicted in 2003 for the 1998 sniper-style murder of Barnett Slepian, an American physician from Amherst, New York who performed abortions.
Question : Which crime James Charles Kopp is considered to have commited?
murder