Carrie Grethen

Carrie Grethen is one of the main antagonists of the Kay Scarpetta series by Patricia Cornwell, the earliest saga of the series where she's associate with crimes throughout her time in the series. Grethen appears in The Body Farm, From Potter's Field, and has a final appearance in Point of Origin.

Grethen was a federal programming consult and lesbian girlfriend of main character Kay Scarpetta's niece, Lucy Farinelli. Grethen would eventually turn to treason when stealing high-level classified federal data with Farinelli's ID as well as associate with a couple serial killers, Temple Gault and Newton Joyce.

The Body Farm
Grethen is introduced as Farinelli's girlfriend and teammate at Quantico. Scarpetta and Farinelli soon find Farinelli's ID has been used to steal top secret information at the naval base, but Farinelli's innocent. It's revealed Grethen is the thief, having stolen her ID to gain access for information to deliver to on-the-loose serial killer Temple Gault. Before she can be arrested, Grethen escapes and goes into hiding with Gault.

From Potter's Field
When Gault resurfaces, Grethen assist in the murder of corrupt Virginia sheriff Lamont Brown, tying a trash bag around his head with a shoelace and shipping him directly to Scarpetta's morgue at 3 in the morning. Gault is eventually killed by a joint effort of Virginia and New York law enforcement, Grethen somehow being captured by unknown means.

Point of Origin
Grethen escapes from a psychiatric penitentiary and associates with a new serial killer, Newton Joyce, encouraging the murderer to change an MO of dismemberment to fire by teaching about pyrophysics. Grethen sends an insanely written, grandiose letter in a threatening word salad hinting at how the duo plans to lure Scarpetta into the case. Scarpetta's boyfriend, FBI Agent Benton Wesley, ends up faking his death to the MO of the killer team at the behest of his superiors, which Scarpetta is grief-stricken to find out and assumes it's an attack from the duo. It would be revealed in later novels Wesley is still alive and he reconciles with Scarpetta. But the fire murders do lead to one thing: when Joyce's identity is discovered and his home is raided, a fridge with the faces he cut off his victims is found to be filled with over 20 faces. Scarpetta realizes Grethen chose a serial killer she was finding but could never catch, a murderer of college students in Virginia who were reduced to little more than headless torsos, to disguise their faces being taken. That fully makes her crash, and Farinelli and Farinelli's boss TN McGovern take Scarpetta back on their helicopter to plan their next move. But in a climactic twist, Grethen and joyce appear in their own helicopter, trying to ram the ladies and shoot at them to make them crash. But taking advantage of the aerodynamics, the three women turn the tactics on the duo, ram the other copter, and cause it to explode in midair, killing both instantly and leaving the burning to crash into the sea.

Victims

 * 1994:
 * Lucy Farinelli (stole her identity; framed for federal theft)
 * Quantino: Victimless theft of federal data
 * 1995:
 * Sheriff Lamont Brown (killed by Gault, then helped dress and ship to Scarpetta's morgue)
 * 1996:
 * Joyce's fire victims (abetted in crafting Joyce's MO)
 * Marlene Farber
 * Austin Hall
 * Claire Rawley
 * Nineteen of Kenneth Sparks' horses
 * One of Kenneth Sparks' horses (attempted; they escaped the fire)
 * Kellie Shephard
 * The attempted helicopter crash (attempted to ram and shoot down their helicopter with Joyce; the duo died in a helicopter crash instead):
 * Kay Scarpetta
 * Lucy Farinelli
 * TN McGovern

Trivia

 * Grethen could possibly based off Veronica Compton, a women who attempted a copycat murder off the Hillside Stranglers at the behest of one of the killers, Kenneth Bianchi, to make it seem like the killers "were innocent". Compton has shown one of the most notorious examples of an attraction to dangerous felons, clinically known as hybrstophilia.