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Crime Scene Investigator Network

Crime Scene Investigator Network Newsletter

MAY 2011
Welcome to the MAY 2011 Crime Scene Investigator Network Newsletter

The Fluorescein Method
of Latent Blood Detection

Ricardo Tomboc, CLPE, CSCSA
Forensic Specialist II
San Bernardino (CA) Police Department

Trying to find traces of latent blood at a possible crime scene is always very challenging, especially when the supposed crime scene has been thoroughly cleansed several times. There are several options available to the Crime Scene Forensic. BlueStar, Luminol, and Florescence are only some of the more particle techniques for use on larger scenes. Although I will be focusing on the Fluorescein Method of Latent Blood Detection; the other techniques may be just as viable.

Fluorescein can be obtained in various forms. Depending upon the formulations that are being followed, mixing a batch can be complex. However, there are prepackaged kits that can be obtained from various vendors that make it as simple as "just adding water"! Two such kits are sold under the registered trademark HemaScein, and another vendor under the trademark Flora-Scene. Since HemaScein, Flora-Scene, and Fluorescein are the same basic formulations, this paper will refer only the chemical name Fluorescein.

Fluorescein is a presumptive blood test for latent bloodstain detection. It has been used in forensic applications to reveal trace amounts of blood. Traces of latent blood can be detected even after repeated cleansing of the crime scene. Fluorescein is highly sensitive to the hemassociated molecules (enzymes and iron) in the red blood cells, (1:105,000 depending upon the dilution rate of the working solution). Traces of these hemassociated molecules will embed themselves on the substright, even after multiple cleanings. Fluorescein can also be used to discover and enhance shoe tracks leading from a bloody crime scene thus allowing investigators to follow the suspect's trail. Fluorescein can be used to locate traces of latent blood on clothing, even after it has been laundered several times (best preformed at the lab). It can also be used on vehicles (inside and out). Some studies have been conducted on the development of bloody latent finger/palm prints. There are two basic forms of Fluorescein that are typically used in forensics.

Fluorescein can be either aqueous or alcohol-based. Both formulations will work. However, alcohol-based solutions are more difficult to make, and can be very volatile, and extreme caution must be taken when used. An open flame or static electricity can ignite the alcohol fumes possibly causing an explosion.

Both Fluorescein and Luminol are on the suspected list of carcinogens yet; Fluorescein has a Food and Drug Administration (FDA) approval for medical usage. Since the 1960's Fluorescein has been used to diagnose blood flow status in the retinas by injecting it directly into the vessels of the eyes, and as a topical used in diagnosis of corneal abrasions, ulcers, infections & dry eye. Other medical applications of Fluorescein include injecting it into the blood system to study the blood flow to tumors, grafts, etc. (also known as Fluorescein mapping) along with other medical diagnostic procedures. Nevertheless, caution should always be employed when using either aqueous or alcohol protocols. The other chemicals used in the aqueous-based Fluorescein formula are zinc and sodium hydroxide, both of which can be commonly found in most households. Again, proper handling and disposal of all reagents should be employed at all times.

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*Article submitted by the author

In This Issue

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New CSI and Forensic Job

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Crime Scene Investigation
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Crime Scene Investigation

Crime Scene Investigation
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Featured Video Presentation

Casting Tool Mark Impressions with Mikrosil

    Learn the basic technique for casting tool mark impressions with Mikrosil.

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New CSI and Forensic Job Announcements

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CCBI Agent   |  Wake County, NC
Final Filing Date: May 13, 2011
Salary: $19.74 - $26.32 per hour

Investigates crime scenes located or initiated within the County's jurisdictional area. Aids in the identification of criminal suspects. Interviews witnesses or victims, determines the scope of investigation and methods to be utilized in gathering evidence. Gathers and maintains custody of physical evidence for scientific evaluation and court display. Processes and tests evidence in the lab using a variety of chemicals and equipment. Prepares detailed reports regarding observation and activities. Testifies in court.

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Forensic Scientist I  |  Phoenix, AZ
Final Filing Date: May 16, 2011
Salary: $42,390 - $62,275 per year

Forensic Scientists apply the physical sciences to the investigation of crimes by performing laboratory analyses on physical evidence. Forensic Scientist I is a closely supervised, non-classified, trainee-level position that is the first classification in the Forensic Scientist series. The training program is designed to provide the Forensic Scientist I with comprehensive instruction in the scientific analysis of physical evidence and will include classroom work, extensive required reading, research and presentation, as well as the successful completion of a mock court program. Guidance and supervision is received from highly trained Forensic Scientists.
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Forensic Analyst  |  Eugene, OR Police Department
Final Filing Date: May 20, 2011
Salary: $28.15 - $35.89 per hour

Performs a variety of complex and specialized technical tasks collecting, preserving, and identifying criminal evidence at crime scenes and / or analyzing evidence in the laboratory; analyzes evidence in conjunction with investigation activities and provides expert testimony in court on methods and results of analysis. This position's responsibilities are heavily weighted on Forensic Video Analysis and Crime Scene Reconstruction.

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Crime Scene Investigator  |  Grand Prairie, TX Police Department
Final Filing Date: May 20, 2011
Salary: $36,081 - $43,680 per year

The Crime Scene Investigator will perform a variety of highly skilled technical criminal identification tasks both in the field and in the laboratory. This includes developing, comparing and identifying latent fingerprints; searching for, collecting, preserving and identifying physical evidence found at crime scenes; photographing and sketching crime scenes; preparing comprehensive and technically correct reports; and testifying as an expert witness in court proceedings.

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AFIS Operator I  |  Alaska Department of Public Safety
Final Filing Date: May 26, 2011
Salary: $3,582.00 per month

This position is responsible for the processing of fingerprints through the Western Identification Network Automated Fingerprint Identification System (WIN/AFIS). The incumbent is responsible for making routine and complex positive identification determinations based on the comparison of fingerprints. The incumbent also actively assists in the automation and integration of identification systems including AFIS, live scan and the automated criminal history records repository and associated tracking systems. This position works with various criminal justice agencies to ensure compliance with Alaska laws regarding associated criminal justice matters.

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