premise: Both charges carry a penalty of up to life in prison. The federal charge also carries a fine of up to $250,000.
  Kopp's whereabouts remain unknown. He was last seen Nov. 3, the day before authorities issued a material witness warrant in the Slepian shooting in the hope of questioning him. Until Thursday, they had not called Kopp a suspect.
  Investigators would not divulge the evidence against Kopp but said last month's discovery of a scope-equipped rifle buried near the Slepian home represented a major breakthrough. Slepian, 52, was shot with a rifle.
   what was a major breakthrough?
hypothesis: discovery of a scope-equipped rifle buried near the Slepian home