1. The search for physical evidence at a crime scene must be thorough and systematic.
2. The search pattern selected will normally depend on the size and locale of the scene and the number of evidence collectors.
3. Physical evidence can be anything from massive objects to microscopic traces. Before commencing a search for physical evidence the investigator must be clear in his mind on-
   (a) How to look for
   (b) Where to look for  and
   (c) What to look for.
   These points are discussed in some details below.

If the crime scene is indoor, the investigator must be careful thorough and systematic in his search for traces. Search in a room or other enclosed place like railway compartment of a vehicle should be conducted in a definite order, by clockwise or anti-clockwise movement. Such a team may consist of the leader and four members who are trained in the search for clues. Any one of the following methods of search may be employed by the leader.

(i)    Strip method (ii) Spiral method (iii)Zone or quad method (iv)   Wheel method            

The whole area to be searched is blocked into a rectangle and the four searchers proceed along tracks parallel to one side of the rectangle looking for clues however minuteype the paragraph content here

The four searchers start from a point just outside the area of the crime scene and move along the path of the spiral till they reach the centre of the scene of crime. They cover the entire area in the process of spiralling.the paragraph content here

The entire area to be searched is blocked into a big square. The big square is then conveniently subdivided into small squares which are then assigned to individual searches.

The entire area is covered by a circle. The searchers start from the centre and proceed along the radii. They then repeat the process several times depending on the size of the circle. the paragraph content here

In indoor crime scenes one should not ignore the space concealed behind the door leaf, the portion of the floor covered by carpets, or mattresses, behind and under the trunks, suitcases  boxes and other items of furniture.

Nothing at a crime scene is insignificant. The investigator should bear in mind that the traces, however, insignificant at the first appearance, may prove to be of immense value later. The minute traces must receive the closest attention of the investigator. The position and condition of everything at the scene must be taken proper note of,