California Code, Penal Code - PEN § 790

(a) The jurisdiction of a criminal action for murder or manslaughter is in the county where the fatal injury was inflicted or in the county in which the injured party died or in the county in which his or her body was found.  However, if the defendant is indicted in the county in which the fatal injury was inflicted, at any time before his or her trial in another county, the sheriff of the other county shall, if the defendant is in custody, deliver the defendant upon demand to the sheriff of the county in which the fatal injury was inflicted.  When the fatal injury was inflicted and the injured person died or his or her body was found within five hundred yards of the boundary of two or more counties, jurisdiction is in either county.

(b) If a defendant is charged with a special circumstance pursuant to paragraph (3) of subdivision (a) of Section 190.2, the jurisdiction for any charged murder, and for any crimes properly joinable with that murder, shall be in any county that has jurisdiction pursuant to subdivision (a) for one or more of the murders charged in a single complaint or indictment as long as the charged murders are “connected together in their commission,” as that phrase is used in Section 954, and subject to a hearing in the jurisdiction where the prosecution is attempting to consolidate the charged murders.  If the charged murders are not joined or consolidated, the murder that was charged outside of the county that has jurisdiction pursuant to subdivision (a) shall be returned to that county.