Twenty-two-year-old Tyler Marlatt is charged with first-, second- and third-degree murder as well as robbery and aggravated assault in the Jan. 16 slaying of slaying of 20-year-old Tyler Struble in Lemont.
Authorities in Centre County say Marlatt and others went to Struble's home to claim money from a deal when Marlatt stabbed Struble to death.
Marlatt's girlfriend pleaded guilty to robbery and drug charges.
Marlatt's attorney has said he was acting in self-defense.