Symbolic of a demon tasked with trying to take your life, Jn. 10:10
To dream about a serial killer foretells sadness caused by the misdeeds of others.
If you are the killer in your dream, this means you will be involved in some dishonorable adventure which will damage your reputation.
If you were killed or pursued by the serial killer, this symbolizes enemies who are working against you.
If you dream that the killer spares your life, you are hopeful that an enemy or rival will stop working against you in real life. Be careful about relying on hopes, however!