It has been argued that murder-suicide is best understood from the perspective of suicide. This suggests that the comparatively (vs. white males) low rate of suicide among Afro-American men may carry over to murder-suicides.
Much of the research seems to go back to a report from the 1990s, but there is a more recent dissertation, at the link below, that has some numbers and perhaps helpful literature review.
Also a book chapter with reference list at the second link: