Copycat

In Criminology, a Copycat is a criminal who mimics the crimes, M.O.s, or victimologies of another criminal. It is theorized that criminals of this type copy the crimes of others in order to find their own "style"--or lack thereof.

On Criminal Minds

 * David Walker ("Won't Get Fooled Again") copied the serial bomber Adrian Bale.
 * Will Sykes ("A Real Rain") partially copied vigilante Marvin Doyle.
 * Sarah Danlin ("Jones") copied Jack the Ripper's style of killing.
 * Anna Begley ("Doubt") partially copied Nathan Tubbs.
 * Henry Frost ("Identity") attempted to copy the M.O. of his mentor, Francis Goehring, but failed.
 * Charlie Wilkinson ("Birthright") copied his father, Robert.
 * Chloe Kelcher ("The Angel Maker") copied Cortland Bryce Ryan.
 * Eric Olson ("Zoe's Reprise") copied the styles of many real-life serial killers, such as Jack the Ripper, David Berkowitz, The Mad Butcher of Kingsbury Run, etc.
 * Robert Adams ("Painless") copied the bomb design used by school shooter and bomber Randy Slade, as well as a notable aspect of Slade's M.O.
 * Caleb Rossmore ("True Genius") copied the Zodiac Killer.
 * Herman Scobie ("Unknown Subject"), in an attempt to pass off as him, partially copied the serial rapist Hamilton Bartholomew, a.k.a. "The Piano Man".
 * Dylan Kohler ("Divining Rod") partially copied Rodney Garrett during the former part of his killings.
 * The BAU Stalker ("The Silencer", "The Apprenticeship", "Magnificent Light", and "Perennials") partially copied the M.O.'s of unsubs the BAU apprehended during the course of Season Eight.
 * Willie Kestler ("Perennials") partially copied Russell Smith.
 * Daniel Dryden ("Killer Profile") copied with full extent several real-life serial killers, including Jeffrey Dahmer, David Berkowitz and Ted Bundy. He also attempted to copy several real-life rampage killers, like Richard Speck, Charles Whitman, and Howard Unruh, but failed.

Real World

 * Veronica Compton
 * Heriberto Seda
 * Stella Nickell
 * Derek Brown