What is a signature and how is it different from modus operandi? In your explanation comment on signature aspect and signature behaviors with examples.
Book:
Petherick, Wayne (2014) Profiling and Serial Crime , Elsevier Publication ISBN 978-1-4557-174-9
Lewis, Dorothy (1998) Guilty by Reason of Insanity, Ballantine Publishing Group ISBN: 0-8041-1887-6 (Amazon. Copy available on Kindle and hard copy.)
Fisher, Joseph C (1997) Killer Among Us, Praeger Publishers ISBN: 0-275-95558-3