Elements that may contribute to a modus operandi:
(1) specific type of criminal act
(2) specific location
(3) make use of a specific tools or technique
(4) specific type of victim
(5) specific things that were or were not taken
(6) specific things not done (carrying a gun, being willing to shoot someone, etc)
If something works then the criminal is more likely to stick to that formula. A unique MO that is used for a long time is helpful for an investigator. An investigator looking for a single MO pattern may be mislead if that pattern changes, as it often does.
Reasons why the MO of a criminal may change:
(1) with experience
(2) with new technologies or skills
(3) with different partners
(4) intentionally to mislead the police
(5) occurrence of an unplanned complication
(6) change in locale or situation
(7) illness or disability
