Toxicologist Found Guilty of Killing Husband

Times Staff Writer

After eight hours of deliberation, a jury Tuesday convicted a former county toxicologist of murdering her husband with an overdose of a powerful painkiller allegedly stolen from her job at the county medical examiner’s office.

Kristin Rossum, 26, burst into tears, shook her head, and looked imploringly at her parents as Superior Court Judge John Thompson announced the verdict. The seven-man, five-woman jury also found Rossum guilty of murder by “special circumstances,” in this case, by using poison.

She looked at the jurors, but none returned her gaze.

Rossum faces a possible life sentence without the possibility of parole when she is sentenced Dec. 12. Prosecutors had opted not to seek the death penalty.


Thompson imposed a gag order on attorneys, witnesses and family members until after sentencing. Jurors fled the courthouse without talking to reporters.

Prosecutors alleged that Rossum killed her husband of 17 months because he threatened to tell her boss that she was using drugs and having an affair with a co-worker, Michael Robertson, the county’s former chief toxicologist.

Robertson, now living in Australia, was listed as an unindicted co-conspirator by the grand jury that charged Rossum with murdering Gregory de Villers, a biotech industry worker, who would have been 29 years old Tuesday.

Prosecutors said that Rossum, who graduated summa cum laude from San Diego State University with a degree in biochemistry, used her knowledge of drugs and chemistry to kill her husband and that she hoped she could convince her colleagues at the medical examiner’s office that the death was a suicide. The medical examiner determines cause of death in unusual cases.

A large amount of the drug fentanyl was later discovered missing from the county office; Robertson, who was fired after admitting that he knew Rossum used methamphetamine, is an expert on fentanyl.

Deputy Dist. Atty. Dan Goldstein alleged that Rossum arranged the couple’s bedroom to look like her husband had committed suicide. His body was found lying on their bed, a wedding photo and her crumpled diary nearby, and rose petals scattered around the room.


Prosecutors theorized that Rossum was re-creating a scene from her favorite movie, “American Beauty,” which includes a fantasy sequence depicting a young woman being showered in rose petals.

One of the most damaging pieces of evidence was a receipt showing that Rossum had purchased a rose on the day her husband died. Rossum had alleged the rose petals in the bedroom were 2 weeks old.

Goldstein, in a withering cross-examination of the tearful Rossum, called her explanation “bizarre” and forced her to concede that she had lied in the past about her drug use and other matters. He called fentanyl “the perfect poison” because it is difficult to detect.

Rossum’s parents had mortgaged their home to raise enough money so she could be freed on $1.25-million bail during the trial. Her father, Ralph Rossum, is a government professor at Claremont McKenna College, and her mother, Constance Rossum, is an associate professor of marketing and management at Azusa Pacific University.

After bailing out their daughter, the Rossums said they lacked money to hire a private attorney. A judge ruled that Rossum was entitled to a public defender.

Even before the verdict was announced, bailiffs had handcuffed Rossum. Weeping and barely able to walk, she was led out of the courtroom and taken to jail.


De Villers’ family watched the verdict without emotion. The family is suing the county, alleging negligence for allowing Rossum to steal a fatal dose of drugs from the medical examiner’s office without being caught. De Villers’ father is a prominent plastic surgeon and liposuction specialist.

Although prosecutors never detailed how Rossum poisoned her husband, there were indications that she may have applied patches containing fentanyl to his arm while he slept. Fentanyl is a rarely applied drug, and the medical examiner’s office seldom tests for it, experts said.

But traces of fentanyl were found in De Villers’ body by examiners.

De Villers’ family was immediately suspicious of Rossum and told police the night his body was found, Nov. 6, 2000, that they did not believe he committed suicide.

Rossum testified that her husband was groggy that night but that she felt he was only showing the effects of a cold medication.

“I thought he was just sleeping it off,” she testified. “I’ve wished every day I’d called someone.”

Prosecutors showed that during the hours before her husband died, Rossum made repeated calls to her lover, Robertson. Fentanyl, often given to terminally ill cancer patients, is 80 times more powerful than morphine.


Jurors deliberated over parts of three days. By comparison, the San Diego jury that convicted David Westerfield on Aug. 21 of murdering Danielle van Dam, 7, deliberated over nine days.