Section 189.5 Of Chapter 1. Homicide From California Penal Code >> Title 8. >> Part 1. >> Chapter 1.
189.5
. (a) Upon a trial for murder, the commission of the homicide
by the defendant being proved, the burden of proving circumstances of
mitigation, or that justify or excuse it, devolves upon the
defendant, unless the proof on the part of the prosecution tends to
show that the crime committed only amounts to manslaughter, or that
the defendant was justifiable or excusable.
(b) Nothing in this section shall apply to or affect any
proceeding under Section 190.3 or 190.4.