[Forensic Life] Why Propofol Death Is 'Murder' Not Suicide

A 119 text message reported that a person had died. When the police and paramedics arrived at the motel where the reporter was staying, they found a man lying straight on the bed, dead, in a room scattered with numerous drug bottles including propofol. The autopsy revealed injection marks on the front and back of the man’s right arm. Diclofenac, propofol, and lidocaine were detected in the skin and blood from the front of the arm. Among these, the blood concentration of diclofenac was about 100 times the therapeutic level and more than six times the toxic level. It was a lethal dose. Diclofenac is originally a painkiller used for arthritis and other conditions. It is very difficult to die from accidental administration of this drug. It could only be concluded that someone had injected a very large amount of the drug into the front of the right arm.

The woman was undergoing treatment in a psychiatric hospital after causing a disturbance by threatening to kill herself. The first investigation of the woman took place three weeks after the incident. The man had met the woman by chance at a karaoke bar. The man was attracted to the woman and ended his relationship with his partner. The woman, a nursing assistant, also had a live-in partner but continued dating the man. However, the woman decided on a joint suicide and claimed that she injected diclofenac and propofol into the IV bag connected to the man’s right arm, and diclofenac, propofol, and lidocaine into the IV connected to her own arm. She insisted that she had injected the same drugs into herself but that the syringe had apparently come out by itself, denying that she had pulled it out, and consistently stated that it was probably due to convulsions caused by propofol.

Propofol has a very short reaction time and is widely used as an induction agent for general anesthesia. It is used frequently for outpatient surgeries or simple procedures such as sedation during endoscopy because recovery is quick and side effects are minimal. Side effects of propofol can include irregular heart rhythms, lowered blood pressure, and respiratory difficulties depending on the individual. It is known that very rarely, convulsions (or seizures) as claimed by the woman may occur; these convulsions manifest as muscle rigidity where the arms and legs suddenly stiffen during a state of muscle ataxia called dystonia. The woman’s claim was a plausible scenario.

Convulsions caused by propofol are a type of drug side effect known as anaphylaxis and can be confirmed through skin prick tests and leukocyte histamine release tests. The woman showed no positive reaction. The police examined the woman’s cellphone contents through digital forensics. It was confirmed that before meeting the man, she had searched for drug-related information, especially articles about how simultaneous administration of diclofenac could cause brain death. The police judged that the woman administered a lethal dose of drugs to the man but only a very low concentration to herself, and charged her without detention under the crime of murder by deception and consent, then sent her to the prosecution.

After supplementary investigation, the prosecution found no searches related to suicide on the man’s cellphone and computer, and no circumstances suggesting he had reasons for an extreme choice. They also found that the woman had strong obsession and suspicion toward the man, and indicted her for murder. The court’s judgment was wise. The first trial sentenced Ms. Park to 30 years in prison, stating, “Ms. Park used her medical knowledge to kill the victim and then took drugs herself to disguise it as a joint suicide.” The second trial upheld the sentence, stating, “Ms. Park claims they agreed on joint suicide, but the victim’s behavior (the day before death) was unlike that of a person planning suicide and showed no signs of suicidal intent,” and “It is difficult to see that they agreed on joint suicide.” The Supreme Court confirmed the second trial’s judgment.

Yoo Seong-ho, Forensic Scientist