Forensics 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 the man's 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. It was Christopher Vaughn, 32-year-old cyber crime and computer security investigator.

The police questioned Vaughn in hospital. Vaughn's initial statement revealed an outlandish story he would cling to during 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 Vaughn's 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 and were instrumental in securing Vaughn's conviction. One of those forms of hard evidence 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 he liked -- was the blood and DNA that provided the evidence required for conviction. Ballistics forensics was likewise instrumental in the Vaughn case, as it would show why Vaughn's story was wrong. The Christopher Vaughn case is one that illustrates some of the core principles of forensic analysis, from the process of collecting bodily fluid evidence from the scene of the crime, to analyzing that evidence and interpreting the results.

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

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

Thankfully, presiding officers...

Improper handling of DNA evidence can lead to its being inadmissible in the courtroom. Key to effective forensics is "the practice of proper collection, storage, and processing of DNA evidence," (Hyde, 2011, p. 5). Likewise, Orthmann & Hess (2013) point out that technologies in DNA collection, storage, and processing have advanced, allowing forensics experts to have access to a wider range of evidence and to enable that evidence to be more reliable in court. "Advances in genetics, genomics and molecular biology are likely to improve human forensic case work in the near future," (Kayser & deKniff, 2011, p. 179).
In this case, it was not necessary to link Vaughn with the scene or with the victims. He was already linked to the scene and to the victims. What was missing was clear evidence that refuted Vaughn's version of the story. The burden of proof rested with the prosecution, who by the laws embedded in the democracy, must work from a foundation in which the suspect is innocent until proven guilty. To prove to the jury what the law officers already intuited was the journey requiring astute applications of forensics science.

Blood started to tell its side of the story. Forensics scientists and technicians gather evidence from the crime scene in different ways, depending on the type of evidence being collected (blood, skin, or hair, for example) as well as the materials the evidence is on. Usually, methods using light or chemicals are used to aid visualization of the fluids. Alternate light source methods are one of the quickest and easiest ways for an investigator to determine whether there is any evidence at all; the chemical tests would then be used to determine what kind of fluid was present. Once the presence of fluids has been identified at the scene of the crime, a series of tests can be performed in a laboratory. Those tests include spectroscopic and microscopic analysis, chemical tests, and enzymatic tests (An, Shin, Yang & Lee, 2012). The results of the analysis can show who's DNA was present in what place.

One of the key ways blood evidence became critical in the Vaughn case was the blood on his jacket. Kimberly's blood was on his jacket. Yet Vaughn clung to a version of the story saying that he fled the scene of the crime after Kimberly shot him. If Kimberly shot him, and then he ran away, there would have been no way for her to bleed on his jacket. Clearly, the blood on his jacket was there because he had shot her first. Second, blood was found on the seatbelts in the car. The placement of the blood on both the driver's side and passenger side seatbelts indicated that Vaughn had already shot his wife and himself when he reached over and unbuckled his wife's seatbelt (Seidl & Wurst, 2012). Third, Vaughn's blood spatter had been found all over the vehicle. According to his story, he fled the scene after being shot. If that were the case, his blood would be nowhere to be found in the vehicle. "Vaughn's blood was found on Kimberly's shirt, Kimberly's shorts, on the passenger side floorboard, and in 17 stains found on both sides of the seatbelt Kimberly was allegedly wearing when she was shot," (Seidl & Wurst, 2012, p. 1).

In addition to blood evidence, forensics analysts also found a singed piece of skin on Vaughn's coat. A forensics test of the singed skin showed it belonged to Vaughn, and was caused by his having wrapped the gun in his jacket to muffle the noise or conceal the weapon (Seidl & Wurst, 2012). There were also significant signs from ballistics reports that Vaughn was lying. Shell casings were found on his seat, for example. Circumstantial evidence such as the fact that Vaughn had "spent time at a shooting range the night before the deaths and fired at targets with a gun that police later found near Kimberly Vaughn in the car," could now take a supporting role to the primary evidence gathered via forensics (Boyle).

The officers and detectives working the Vaughn case relied heavily on their forensics team to secure the conviction of Christopher Vaughn. Vaughn's story was refuted because a team of experts had preserved the crime scene with the integrity necessary to prevent damaging the evidence and rendering it inadmissible in court. Moreover, technicians would have needed to adequately, meticulously, and painstakingly label each and every piece of DNA evidence taken from the scene, cataloging and filing it for records keeping and analysis. As Hyde (2011) notes, there is a "chain of custody" all stakeholders follow as different specialists interact with the evidence in different ways at different times (p. 8). Because the Vaughn case actually took years to process, the evidence had to have been stored properly in accordance with the core principles of forensics, including the use of freezing and also chemical soaking (Orthmann & Hess, 2013).

Because the blood and ballistics analysts were able to eliminate reasonable doubt in the mind of the jurors, Vaughn is now serving an…