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Crime Laboratory Service

 

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The Harris County Institute of Forensic Sciences’ Crime Laboratory performs analyses in the five distinct forensic disciplines of Drug Chemistry, Firearms Identification, Forensic Genetics, Forensic Toxicology and Trace Evidence. The Crime Laboratory is accredited by the American Society for Crime Laboratory Directors / Laboratory Accreditation Board (ASCLD/LAB) under the International Program and by the Texas Department of Public Safety. The Toxicology Laboratory is accredited by the American Board of Forensic Toxicology (ABFT). In addition, the Forensic Genetics Laboratory maintains compliance with the FBI Quality Assurance Standards for Forensic DNA Testing Laboratories.

 

Provides services to the Institute’s Forensic Pathology Service and law enforcement agencies throughout Harris and surrounding counties

The Crime Laboratory provides services to the Forensic Pathology Service and law enforcement agencies in Harris County and the surrounding counties. The Laboratory completed 21,562 cases in 2009, a 14% increase over year 2008. In particular, the Forensic Genetics Laboratory saw a 44% increase in completed cases. The Drug Chemistry Laboratory has improved their turnaround time by completing 90% of cases within 10 days. The Crime Laboratory continues to invest in new technology to improve methods and increase productivity. The Laboratory recently added LC/MS/MS, Headspace GCMS, GC/MS/MS, and Liquid Chromatography/Time-of-Flight/Mass Spectrometer (LC/TOF/MS) instrumentation. The Scanning Electron Microscopes have been upgraded with more efficient X-ray detection systems. To complete the automation of the DNA testing process, the Forensic Genetics Laboratory added three new robotic instruments.

 

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Forensic Genetics

 

Forensic Genetics

 

Click here to download and print the DNA Collection Guide

DNA Presentation
(PPT 41MB)

The Forensic Genetics Laboratory analyzes biological fluids and tissues such as blood, semen, muscle and bone. The DNA contained in these materials is purified and tested to obtain a DNA profile that may link evidence found at a crime scene to an individual.

Analyses biological fluid and tissue for the presence of DNA

Likewise, non-matching DNA profiles can point investigators away from a particular individual. A DNA profile recovered from two or more crime scenes can indicate the same individual was present at more than one crime scene. In addition, DNA testing can establish parentage and can positively identify human remains.

The Polymerase Chain Reaction, or PCR, is used to prepare large quantities of specific DNA regions from small samples recovered from crime scenes. The laboratory utilizes automated genetic analyzers that subject the DNA to capillary electrophoresis to determine DNA profiles.

The laboratory participates in the FBI Combined DNA Index System, or CODIS, a network of local, state and national DNA databases. CODIS links DNA profiles of evidence from unsolved crimes to DNA profiles from convicted offenders and from DNA profiles of other crimes.

 

 
 

 

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Forensic Toxicology

 

Forensic Toxicology

 

The Harris County Institute of Forensic Sciences’ Forensic Toxicology Laboratory is dually-accredited by the American Society of Crime Laboratory Directors/Laboratory Accreditation Board-International testing program and by the American Board of Forensic Toxicology.

The Institute’s Forensic Toxicology Laboratory is equipped with advanced instrumentation to perform testing services

The laboratory provides analytical services in medicolegal death investigations (postmortem analysis), driving while impaired (human performance alcohol and drug testing), and drug-facilitated sexual assault investigations to support medical examiners, law enforcement agencies, the justice system, and other customers within Harris County.

The Institute’s Forensic Toxicology Laboratory is equipped with advanced instrumentation to perform testing services, and its toxicologists apply this wide variety of instrumental techniques in the course of their casework.

Instrumentation and testing services include:

  • Headspace Gas Chromatography (HGC) – Detects the presence of ethanol and other volatile substances.
  • Enzyme-Linked Immunosorbent Assay (ELISA) – Screens for common classes of drugs.
  • Gas Chromatography-Mass Spectrometry (GC/MS) and Liquid Chromatography Tandem Mass Spectrometry (LC/MS/MS) – Confirms and quantifies drugs and their metabolites.
  • High-resolution Liquid Chromatography-Time of Flight Mass Spectrometry (LC/TOF-MS) – Screens for routine and novel drugs of abuse.

 

For more information, read our published work: Validation of LC-TOF-MS screening for drugs, metabolites, and collateral compounds in forensic toxicology specimens


In addition to the confirmation/quantitation of routine drugs of abuse, the Forensic Toxicology Laboratory identifies and reports the presence of so-called “designer drugs,” such as synthetic cannabinoids (“K2”/”Spice”), synthetic cathinones (“bath salts”) and potent phenethylamine hallucinogens, such as the NBOMe drug class.

Learn about the pathological findings of two fatal 25I-BOMe deaths in Harris County: Pathological findings in 2 cases of fatal 25I-NBOMe toxicity

 

 

 

Instructions for Collecting and Submitting Specimens for Toxicological Analysis


Specimen Collection

For full toxicological analysis, it is recommended that the submitting agency provide the following:

  • (Blood) A total of at least 14mL of blood collected in two test tubes with sodium fluoride and potassium oxalate preservatives, i.e., gray-topped tubes (best for DWI)
  • (Urine) 50mL of urine collected in a urine specimen bottle or urine specimen cup (best for Drug Facilitated Sexual Assault)

Each specimen tube, bottle or cup must be labeled with the following:

  • Name of the individual from whom the specimen was collected
  • Date and time of collection
  • Initials of the individual who collected the specimen

 

Each specimen tube, bottle or cup should be stored inside a specimen container, such as a cardboard box, envelope or plastic bag. It is acceptable to include multiple specimen tubes, bottles or cups in one specimen container if they all pertain to the same case. The specimen container should be sealed with evidence tape and must be labeled with the following:

  • Initials of the individual submitting the specimen container – initials must be written across both the tape and the container
  • Name of the submitting law enforcement agency
  • Case number

 

To maintain the integrity of the specimen, a chain of custody should be initiated upon collection and the specimen should be refrigerated as soon as possible.

Submission

  • During regular business hours (Monday through Friday, 8 a.m. – 5 p.m.) – Submit specimens to the Harris County Institute of Forensic Sciences Evidence Reception located at 1885 Old Spanish Trail, Houston, Texas (Click here for detailed Evidence Submission & Testing instructions)
  • Afterhours, Weekends and on Harris County Holidays – Submit specimens at the afterhours evidence submission location, which can be accessed at the rear of the Institute’s building located at 1885 Old Spanish Trail, Houston, Texas.
  • A submission form must be completed at the time of submission and must accompany the submission. Do not attach the form to the specimen container – Click here to download the submission form or request a form from the Institute’s Evidence Receiving staff during regular business hours
Click here to download the submission form or request a form from the Institute’s Evidence Receiving staff during regular business hours.

 

Result Reporting for DWI Testing

In suspected Driving While Intoxicated (DWI) cases, blood specimens first undergo alcohol testing. If the blood alcohol level is greater than or equal to 0.10 g/100mL, no further testing is performed unless specifically requested. If the blood alcohol level is less than 0.10 g/100mL, drug screening and confirmation is performed.

​Identifies and reports the presence of designer drugs such as K2/Spice and bath salts

When the recommended volume of blood or urine is not received, some testing may not be possible. For example, when the specimen sample volume is not sufficient for both drug screening and confirmation tests, positive screening results will be reported as “Presumptive positive.” In these instances, a forensic toxicologist may contact the submitting law enforcement agency to discuss the need for drug confirmation tests. When sample volume is not sufficient for any type of testing, results will be reported as “Quantity not sufficient.”

 

 

 

 

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Drug Chemistry

 

Drug Chemistry

 

Accredited by both the American Society of Crime Laboratory Directors/Laboratory Accreditation Board-International and the Texas Forensic Science Commission

In accordance with Texas state statutes, the Institute’s Drug Chemistry Laboratory (DCL) analyzes suspected drug evidence seized by law enforcement agencies in Harris County. Examples include:

  • Well known drugs of abuse such as marihuana, cocaine, methamphetamine, heroin, and pharmaceutical preparations
  • New and emerging classes of drugs such as synthetic cannabinoids (“KUSH,” “Spice”), synthetic cathinones (“bath salts”), and substituted phenethylamines such as “NBOMes”
  • Clandestinely manufactured tablets which mimic pharmaceutical tablets

 

On average, the DCL completes 7,000 to 10,000 cases each year. Findings are presented in analytical reports used to support the criminal justice system in Harris County.

 

 

Instrumentation used in the Drug Chemistry Laboratory includes:

  • Gas Chromatograph-Flame Ionization Detector (GC-FID)
  • Gas Chromatograph-Mass Spectrometer (GC-MS)
  • Gas Chromatograph-Infrared Detector (GC-IRD)
  • Direct Analysis in Real Time- Time of Flight (DART-TOF)
  • Fourier Transform Infrared Spectrometer (FTIR)
  • Ultraviolet/Visible Spectrometer (UV)
  • CombiFlash Rf+
  • Desktop Nuclear Magnetic Resonance (NMR)
  • Stereoscope with a 12.5-megapixel digital camera attachment

 

 

 

 

 

 

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Trace Evidence

 

Trace Evidence

 

The Trace Evidence Laboratory offers services involving the two forensic sub-disciplines of Gunshot Residue Analysis and Fire Debris Analysis.

Provides gunshot residue and fire debris analysis

Gunshot residue analysis is performed utilizing Scanning Electron Microscopy/Energy Dispersive Spectrometry (SEM/EDS). The micron-sized particles from the discharge of a vast majority of ammunition primers can be identified by the presence of lead, barium, and antimony.

The laboratory also offers the analysis of fire debris samples for the presence of ignitable liquid residues. Samples of debris from suspicious fires are submitted and analyzed by chemists for the presence of gasoline, petroleum distillates, and a wide-ranging variety of other ignitable liquids. The analysis is performed with gas chromatography with mass-selective detection. Two members of the staff are board certified by the American Board of Criminalistics.

 

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Firearms Identification

 

Firearms Identification

 

The Firearms Laboratory evaluates fired cartridge casings and bullets recovered from crime scenes, and firearms involved in violent, gun-related incidents. Typically, microscopic markings on recovered cartridge cases and bullets are compared to markings made by a suspect’s firearm, or if no firearm is recovered, then a comparison is made to cartridge cases stored in a database. Often the type and manufacturer of the firearm can be determined by laboratory examination of the cartridge case or bullet in the absence of the firearm.

Evaluates fired cartridge casings and bullets recovered from crime scenes, and firearms involved in violent, gun-related incidents

The Firearms Laboratory participates in the Integrated Ballistics Imaging System (IBIS). IBIS stores and compares images of fired cartridge cases from crime scenes to images of cartridge cases test fired from recovered firearms. Through the use of this technology, the Firearms Laboratory can link recovered firearms to unsolved crimes.

Serial number restoration is another service performed by the Firearms Laboratory. This capability can assist in the identification of a weapon, even when the manufacturer’s serial numbers have been filed off. This can assist investigations in many ways. For example, it may allow a stolen firearm to be returned to its legal owner by using E-Trace, a web based application that allows firearms to be traced via the National Tracing Center of the Bureau of Alcohol, Tobacco, Firearms and Explosives. Firearm tracing can aid investigators in seeking to identify sources of crime guns and ‘straw’ purchases.

 

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