black on black crime

black on black crime = black people committing serious crime?

Context:

Cougarbate (0 friends, send message) wrote: 21m ago
alphamom10 (46 friends, send message) wrote: 48m ago
have we heard from al & jesse yet? i haven't seen their "fine hand" in any of this....is it b/c this is black on black crime?
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The ghouls are too busy dining on MJ's corpse.
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These malicious comments shows why the "cracka' always crumble.

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http://content.usatoday.com/community/comments.aspx?id=35613148.story&p=1