Considering that Crowley claimed to have gathered information from her while outside Mr. Gates' house, and she denied having told him anything at the scene... That should actually be enough to cast doubt on Sgt. Crowley's professionalism during the incident - why should he make something up when his conclusions and his actions were perfectly fine?
Or perhaps he confused something there, like, who told him what, and if anybody at all told him that or he just imagined somebody having told him something specific. This wouldn't exactly be a sign of lack of professionalism, but being confused about certain details rarely helps your case.