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Forensic News

By External Source 20 Oct, 2016

Crime scene technicians are responsible for photographing, looking for latent prints, and collecting evidence at crime scenes. Because of crime volume, crime scene technicians do not respond to all crime scenes. Many departments rely on specially trained officers or public safety aides to handle crime scene processing of less violent offenses, such as motor vehicle thefts and burglaries of homes and vehicles.

Training of officers for this time-consuming and methodical work is often a limited, one-time event. Refresher courses on crime scene processing are typically not offered, providing minimal assurances that officers are following protocol or handling evidence properly. Without periodic training, officers are also not exposed to changing technology or more efficient methods of crime scene processing and evidence collection.

Challenges of Crime Scene Processing

Every crime scene is different and involves decisions such as whether to process evidence at the scene, collect evidence for later processing at the crime laboratory, or request assistance from the crime scene unit. When deciding how to approach latent print processing, factors that may affect the method include weather conditions, contamination of evidence, and whether the evidence is on a porous or nonporous surface.

Weather becomes an issue when it is raining and the officer is faced with processing a soaking-wet vehicle. The best course of action is usually to tow the vehicle to a police facility to allow the vehicle to dry before processing. If this is not an option, the second-best option is to ask the victim to call for processing when the vehicle is dry. If neither of these options is available, the officer is often limited to processing items inside the vehicle for latent prints and possible DNA. Touch, wear, or saliva DNA can often be found in a burglarized vehicle.

DNA should be the officer’s first focus. Collecting it would involve taking a sterile swab lightly dampened with distilled water and swabbing the steering wheel, turn signal, gear shift, and edges of the rearview mirror. Inside the vehicle, there may be other miscellaneous items that the officer may decide to swab such as drink cups or cans, cigarette packs, or cell phones. If the victim is available, the officer should ask him or her to carefully look inside the vehicle to see if they see anything that does not belong to them, and therefore may have been left by the perpetrator.

After carefully collecting possible touch DNA swabs, the officer should process the following locations for latent prints:

  • Dash and console
  • Rearview mirror and all windows
  • Metal portion of seatbelts
  • Miscellaneous items in the console, on and under the seats, and on the floor
  • Items contained in glovebox and trunk

The decision whether to process items found inside a burglarized home or vehicle often hinges on whether or not the item is porous or non-porous. Porous evidence consists of items that, when touched, will absorb fingerprint residue like a sponge. Examples would be unfinished wood, paper, cardboard, and fabrics. Non-porous evidence consists of items that, when touched, will preserve the latent print on the surface unless disturbed. Examples of these would be glass, metal, and plastics.

Non-porous items can be processed at the crime scene using black or gray powder and a fiberglass brush. More advanced methods of chemical processing for non-porous evidence include superglue fuming and enhancement with powder or fluorescent dyes. If the officer suspects the object may have belonged to or been touched by the suspect, the best decision would be to collect and preserve the evidence for latent print processing in the crime laboratory.

Porous items usually respond better to chemical processing methods, such as iodine or ninhydrin, than the application of fingerprint powder. Vehicles that have been exposed to rain or heavy humidity will often have damp miscellaneous paper items scattered in the vehicle or in the glove box that will need to be dried before processing. There are some chemicals, such as Oil Red, which develop prints on damp paper more efficiently than ninhydrin or iodine. Paper items that have recently been touched react well to processing with magnetic powder; however, as a basic rule officers should collect paper items and submit the evidence for processing in the crime laboratory.

Specially trained patrol officers and public safety aides play a crucial role in solving crimes by assisting the crime scene technicians with less violent offenses. Periodic training in crime scene processing can assist these officers, which is beneficial to any police department. Citizens in the community who are victimized expect law enforcement to respond to burglaries and motor vehicle thefts and identify suspects. The more efficient officers are in processing evidence, the more time they will have to answer other calls.

By External Source 05 Oct, 2016

FORT MYERS, Fla. — Although Jan Cornell never stopped hoping for closure in the brutal 1990 murders of her daughter Robin Cornell and roommate Lisa Story, she calls the arrest of a suspect   nothing short of a miracle.

Cape Coral police Chief David Newlan announced Wednesday that Joseph Zieler, 54, of North Fort Myers, was arrested for the murders of Story and Cornell. “It was like winning the lottery of justice,” Cornell said. “Every prayer, every word, everything, came full circle.” 

Cornell was at her boyfriend's home on the evening of May 9, 1990, watching television when she fell asleep. When she returned home she discovered that her daughter, 11, and roommate, 32, had been killed inside the apartment. Zieler was in Lee County jail on a felony aggravated battery charge for shooting his son with a pellet gun in August when a DNA test matched him to evidence found at the scene of the murders 26 years ago.

Zieler, who was 28 at the time of the double murder, will face five charges, including two counts of sexual battery, one count of burglary and two counts of first degree murder. He is scheduled to have his first appearance for these charges Thursday morning in Lee County court. Jan Cornell said there was no way to describe how she felt when police came to her home Monday to give her the news.

“It was a miracle,” she said.

Cornell said she has no idea who Zieler is, has no connection and no information on the man who has been implicated in the double murder. “I’ve looked at every outlet to see where there might have been a connection,” she said. Cornell credited the 2009 law that requires DNA testing for those arrested for felonies for helping break the case.

“When you are looking for someone who killed people you loved you just get more hope,” she said. ”If (Zieler) never got in trouble this case would never be solved. This is the beginning of the end.” The Lee County Sheriff’s Office notified Cape Coral police when Zieler's DNA received a hit on CODIS, Newlan said. Further DNA from Zieler was obtained and tested by the Florida Department of Law Enforcement. The results came back positive with evidence collected in the apartment at Courtyards of Cape Coral Condominiums.

"We got him," Newlan said. “This brings closure to the family. Twenty-six years is a long time.”

The arrest closes the city's longest open homicide. The case has drawn attention over the years airing on   America’s Most Wanted  three times as well as on other similar crime shows and in dozens of publications. Police officers and others involved in the case shared Cornell’s elation. “To tell you the system works is the best thing ever,” said Christy Jo Ellis, chief investigator for the Cape Coral police. “I’m over the moon. It was so surreal when I got the phone call. I said, ‘Are you kidding me?’”

Ellis said that the case is on track to being solved makes her feel great as she approaches the 25th anniversary of her police career, adding that she always believed the case would be solved. “It’s just phenomenal,” she said. “We have the lock, we just need the key.”

She said Zieler's arrest was a welcome surprise.

“This guy has been off the radar for 26 years,” she said, noting Zieler has been in the community the entire time, 20 years at his North Fort Myers address, seeing the yearly updates. “Because he had an arrest in 2016 and due to a DNA swab it just shows that the system works.” Barrett Walker, Ellis’ supervisor in the major crimes unit, said that the department is building a case.

“Now we have to organize the case. We have other evidence,” he said, adding that Zieler has not confessed to the crime. “We still have a lot of answers we need to get to.” Walker said those who knew Zieler in the 1990s or knows him now need to contact the Cape Coral police. Steve Russell, the 20th Judicial Circuit State Attorney, said the arrest of Zieler and subsequent prosecution should give hope to victims’ families and fear to those who commit crimes that cases can be solved at any time.

“The Cape Coal Police Department never let this go away,” he said.

Newlan, Walker, and Ellis all stressed that the double murder was not a cold case and that it never became a case that languished. “A lot of detectives have kept in touch, different generations of law enforcement,” Newlan said. Walker cited the evidence-gathering chain from the initial investigation. “It makes us proud of what we were and proud of what we are,” he said. “They documented and preserved evidence the right way.”

By External Source 29 Aug, 2016

The core tenet of physical evidence collection is that an offender leaves traces behind at a crime scene – while taking other traces with them. The concept is Locard’s Exchange Principle, and has been increasingly applied to fingerprints, body fluids, touch DNA, pollen, and near-invisible signs of contact.

Could perfumes and colognes be the next clue?

Key parts of chemical signatures are transferred by direct contact, according to a new study by University College London researchers in the journal  Science and Justice .

“While there is a lot of work in forensic science on transfers – for example, the transfer of fibers or the transfer of gun-shot residue – until now there has been no research on the transfer for perfumes,” said lead author Simona Ghergel, a doctoral student, in a UCL statement. “We thought there was a lot of potential with perfume because a lot of people use it. We know about 90 percent of women and 60 percent of men use perfume on a regular basis.”

A series of volatile organic compounds are in a wide variety of common perfumes and colognes. Some of the most common are limonene, linalool, geraniol, eugenol, and coumarin.

The UCL researchers concocted a test mixture that includes those key chemicals, as well as other assorted ingredients included in many scents. Samples of the test perfume were allowed to dry and “age” prior to the experiments – for as short as five minutes, to six hours or even seven days.

Then they conducted a series of experiments to determine whether direct contact, or rubbing, could transfer the signature. The contact was as quick as one minute, and as long as an hour. Rubbing with a gloved hand lasted two minutes. The subject surfaces were then measured for microscopic traces by gas chromatography-mass spectrometry.

The transfer depended on how strong the perfume was, how it aged, and how long the contact was. But transfer happened . Direct contact for just one minute left behind 15 components of the original 44 in the signature, they said.

The drawback is – the evidence disappears after it is collected. It would need to be analyzed almost immediately, they said. “There might be a considerable time delay between the crime and the collection of the evidence, in addition to a delay from collection to the analysis of the evidence, which can make an accurate interpretation of perfume trace evidence difficult,” they write.

Even though the proof-of-concept experiments won’t immediately translate to crime scenes, they contend they could eventually part of an important toolkit, particularly when it comes to sexual assaults.

“Due to the close contact between the victim and assailant during sexual assault, fragrance analysis has the potential to be an additional forensic tool that could be used to demonstrate a contact has taken place, and potentially indicate thy type of contact made and the timeframe since the contact,” they contend.

The potential for first measuring odor in textiles was proposed by a Polish scientist in 2003, in an industry journal. However, the scientist contended such analysis would require massive research to properly quantify.

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