|Cause of death||Shot by Molly Trettel and Police SWAT sniper|
|Family||Molly Trettel (wife)|
Annie Trettel (daughter)
|First Seen||“The Alchemist”|
|Last Seen||“The Alchemist”|
Eric Trettel was a member of The Blacklist who helped clients fake their own deaths.
Eric Trettel was a medical school student, but after failing his courses, he forged a Harvard University degree and gained employment on the Human Genome Project. He then used those credentials to make a career as an expert witness. He was exposed as a fraud after the trial of Carlos Trena, a mafia "soldier" suspected of 3 murders, went wrong because the exculpatory DNA evidence he provided was proven false. Trettel then went underground and became "The Alchemist". Using his intricate knowledge of forensics and genetics, he would seek out people resembling his clients, who were criminals about to face trial, alter their physical appearances as closely as possible and even turn their DNA into theirs using artificial DNA and kill them, faking the clients' deaths and allowing them to disappear. He enjoyed the challenge of pushing the limits of science. Raymond Reddington admitted that Trettel had the superior skill set for making people disappear.
Trettel fakes the deaths of Pytor Madrczyk, a mob informant, and his wife, Catherine Madrczyk, in a plane crash, killing 2 innocent people and the crew in the process. He later killed both of them after the FBI captured Pytor and began a hunt for Trettel. After realizing that the FBI was close to locating his laboratory, he kidnapped Molly, his wife and Annie, his daughter, faked their deaths and attempted to flee. At a filling station/convenience store, Molly tells him that Annie is diabetic. Annie is shown on the television in an AMBER Alert and the clerk attempts to telephone the police. Eric pulls out his gun, telling him to get off the phone; another man pulls out a revolver and Eric shoots him, unintentionally causing the man to shoot Annie. As Molly tries to stop the bleeding, Eric accidentally leaves the man's gun near her and Molly shoots him while he was talking to Elizabeth Keen. It is unknown if the daughter survived.
- Pytor and Catherine Madrczyk
- Unnamed businessman behind a Ponzi scheme
- Unnamed Mafia boss
- Unnamed paedophile priest