Forensic Blood Evidence and the Christopher Vaughn Case

Introduction: The Christopher Vaughn Crime Scene

On June 14, 2007, a man covered in blood waved down a passing motorist on Interstate 55 in Illinois. He had gunshot wounds in the arm and leg. It was 5:40 in the morning in Channahon Township, Illinois. Nearby, the man's 2004 Ford Expedition carried the dead bodies of his wife and three children, ages 12, 11, and 8. They had all been shot to death. After pulling over, the motorist phoned 911, and the man was rushed to hospital. He was Christopher Vaughn, a 32-year-old cyber crime and computer security investigator.

The police questioned Vaughn in hospital. His initial statement revealed an outlandish story he would cling to throughout the course of his defense. Vaughn claimed that his wife asked him to pull over, then suddenly pulled out a gun, shot at him, killed her three children, and finally shot herself dead. The police did not believe Vaughn then, and neither would the jury, who would years later convict Christopher Vaughn of first-degree murder. It also did not help Vaughn that officers later found a magazine article in his home detailing how to "stage crime scenes" and how to "make the death appear a suicide" (Boyle, 2012).

There were several forms of hard evidence used in the trial that were instrumental in securing Vaughn's conviction. One of those forms was, ironically, computer records. Vaughn had worked for a long time as a computer security expert and even as a private investigator specializing in digital data. Yet far more incriminating than what was on Vaughn's computer files — which were mainly photos of camping trips and information linking Vaughn to several strippers — was the blood and DNA evidence that ultimately provided the basis for conviction. Ballistics forensics was likewise instrumental in the Vaughn case, as it would show why Vaughn's story was impossible. The Christopher Vaughn case illustrates some of the core principles of forensic analysis, from the process of collecting bodily fluid evidence at a crime scene, to analyzing that evidence and interpreting the results.

The Role of Biological Evidence in Forensic Investigations

As An et al. (2012) point out, biological samples play "pivotal roles in forensic investigations" (p. 545). The biological fluids acquired from sampling both the scene and donors can elucidate clear links between a suspect and the crime scene and its victims. Moreover, in cases like that of Vaughn, bodily fluid analysis helped to differentiate Vaughn's tale of his wife committing a dramatic murder-suicide from the truth — that Vaughn killed them all and shot himself lightly to make it appear he was innocent. The suspect owned the car, making the simple presence of his DNA insufficient for a conviction. The prosecution needed the blood to tell a story, and eventually it did.

Toxicology Findings and the Challenge to the Prosecution

Vaughn shot his wife Kimberly under the chin. When her body was found, the gunshot wound was visible and blood had streamed onto the car console (Haggerty & Walberg, 2012). Toxicology reports on Kimberly's body revealed the presence of an anti-seizure medication called Topamax and the antidepressant drug Nortriptyline. According to forensic pathologist Larry Blum, "the amount of Nortriptyline found in Kimberly's system was just at toxic levels," and "both drugs could cause suicidal thoughts" (Seidl & Wurst, 2012). Blum's testimony could have been a major setback for the prosecution, because it allowed for reasonable doubt. If Kimberly was on medication that might have altered her ability to think rationally — and especially on medication that might have inspired suicidal ideation — then she might conceivably have been capable of at least killing herself.

There were no live witnesses to corroborate her side of the story, and without a confession, the prosecution faced an uphill battle in showing that it was indeed Christopher Vaughn who had committed a quadruple murder in the space of a single evening.