A crime scene can occur anywhere and at any time of the day. So the method chosen for searching a crime scene is basically determined by where and when the crime occurs.
The popular methods used to search a crime scene include: spiral, strip/line, grid, zone/quadrant, and pie/ wheel.
Crime scene searches and evidence collection are the backbone of criminal investigation. If the crime scene boundaries are not adequately identified, with an appropriate search and systematic identification and collection of evidence to follow, then cases may not be prosecutable.
The spiral search is used most often for outdoor crime scenes, is conducted by one person, and is done by walking in a circle from the outermost point of the inner perimeter toward the center of the circle.
The strip/line search is done by dividing the crime scene into a series of lanes in which personnel search up and down the lanes until the scene is completely searched.
A grid search is similar to a strip/line search but is also divided into lanes perpendicularly, thereby constituting a more systematically thorough search from multiple perspectives.
A zone/quadrant search is one in which the crime scene is divided into four quadrants and searched using another method, such as a strip or line search.
In a pie/wheel search, the crime scene is divided into a large circle with numerous sectors, and searched using another method, such as a strip/line search.
Practically speaking, a strip/line or grid search is used most often (Swanson, Chamelin, and Territo 2003).
For more info on processing a crime scene, refer to links below:
what-when-how.com
updmysteries.com
legalbeagle.com
www.universalclass.com