Criminal Defense Lawyers know that upon arrival at the location of a crime, the crime scene investigators, or detectives, assume charge of the scene. They may require the assistance of the uniformed officers for perimeter control, crowd control, media access, and security. If they require no further assistance from the uniformed officers, the detective in charge may dismiss them to continue their patrol duties. At this point the investigation begins. Criminal defense lawyers will be most concerned with the manner in which any investigation is undertaken. Detectives use a variety of means to solve crimes of all types. Those means can be as simple as speaking with witnesses. Investigators can also use any number of scientific tests to aid them in mounting evidence against an suspect.