Expert testimony on gangs?

CrimLaw links to Style Weekly article about a trial which "marks the first time gang experts have been allowed to testify in Richmond Circuit Court." The trial court judge, the Hon. Margaret Spencer allowed evidence during the sentencing phase from "Mindy Drizzard, a probation and parole officer with the Virginia Department of Corrections and member of the attorney general’s gang task force, and Richmond Police Sgt. Tommy Lloyd, with the department’s gang intelligence unit," and they "identified Servellon’s tattoos as consistent with those worn by members of the notorious Cuban gang the Latin Kings."