Final answer:
The excerpts provided do not offer information on Assistant DA DeLaughter finding a murder weapon or the methods used for its discovery.
Step-by-step explanation:
The provided excerpts do not explicitly mention Assistant DA DeLaughter or the discovery of a murder weapon in any specific location. These passages seem to belong to different narratives where characters are investigating a crime or reflecting on violent events. The text refers to various law enforcement and legal situations where characters are either looking for evidence or contemplating past violent incidents. One passage discusses the need for a motive in a murder case, implying that finding the weapon could provide such insight. In the case of Jennifer Thompson mentioned, it outlines the issue of mistaken identity, which could lead to a miscarriage of justice, but does not provide information on the specific whereabouts of a murder weapon or how an Assistant DA might know of its location.