The Gang's All Here - I see em in Court!

In cases where multiple defendants are allegedly members of gangs, the Government loves to bring in "expert" witnesses on how gangs operate, hierarchy, etc.  It makes for compelling testimony for the jury.  But sometimes the Government takes its witnesses a little too far.  In United States v. Rios, the Court held that a witness will not be a proper FRE Rule 702 witness where they mix fact with their expert testimony on the particular gang under indictment.  In Rios, one of the witnesses testified as the lead investigator, as well as an expert witness on gangs.  The witness not only informed the jury about how the particular gang worked, but peppered in his personal observations to support the expert testimony.  The Court found that " it is difficult to parse what came from Haglund the expert and what came from Haglund the investigator because there was no clear demarcation between his fact and expert testimony during the trial. This confusion regarding the capacity in which Haglund was testifying is independently problematic. The district court did not delineate Detective Haglund’s testimony—and Haglund himself never distinguished between his fact and expert testimony."  Therefore,  "even if Haglund’s testimony did not exceed the scope of Rule 702, his overall presentation as a dual fact-expert witness without further demarcation or explanation to the jury was in error."  Unfortunately for the defendants, however, the Court went on to find such error harmless under the circumstances of the case.