A "red ball" is Baltimore Police Department terminology
for a top priority case. Red ball cases are handled
by the homicide unit, regardless of whether the case
involves a murder. When a red ball appears, work on
all other pending cases is suspended, and all
homicide personnel and resources are temporarily
reassigned until the case is closed or completely
stalled. Red ball cases tend to fall into one of the
following categories:
By way of example: both the murder of eleven-year old
Adena Watson on Homicide: Life on the Street, and
Latonya Wallace, the real-life case which inspired
it, were red ball cases.
This term was first introduced to the general public
by David Simon's memoir of a year spent with the
homicide unit of the Baltimore Police Department,
Homicide: A Year on the Killing Streets, and
introduced again to a much larger audience by the TV
series the book inspired, Homicide: Life on the
Street. Interestingly, the term also appears in the
movie Minority Report (but not the original Philip
K. Dick short story), in which it refers to a murder
case with little to no premeditation, which requires
a similar degree of urgency. I believe that this is a
direct nod to the actual Baltimore tradition; while
the movie takes place in Washington, D.C., the lead
character is noted to have started his police career
in Baltimore.
The exact etymology of this phrase is uncertain, but
it appears to be derived from railroad terminology,
in which a red ball is a fast freight train which has
priority over other trains on the track. Given the
importance of Baltimore in railroad history, vis a
vis the Baltimore and Ohio Railroad, this derivation
seems quite plausible.