Two detectives not only walk around a crime scene and handle potential evidence without gloves, but allow a suspect to accompany them and touch potential evidence as well.
Simply lying to people is not "gaslighting". Gaslighting involves a protracted subjugation of a subject in a series of forced perceptions and illusions designed to allow the subject to fool themselves into believing the intended results. Derived from the 1944 film "Gaslight". It is not just another word for lying.