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Crime Lab & Forensic Scandals


2012 – FBI testimony on microscopic hair comparison found to be unreliable, starting a review of more than 21,000 cases handled before 2000.


2014 - Crime lab analysts in San Jose were found to be using the wrong chemical to conduct preliminary methamphetamine tests on over 2,500 blood samples from those arrested on suspicion of being under the influence of a controlled substance. The samples were retested, and only seven of those tested showed a false positive because of the different chemical.

2013 – George Souliotes was convicted of setting a house fire that killed a woman and two children in 1997. His conviction was based on arson evidence that has since been discredited. The California Attorney General admitted that the arson evidence used in the case was faulty and that there is no scientific evidence that the fire was in fact arson. Souliotes remains in prison as prosecutors fight to delay his release.

2010 – The California Department of Justice found that quantities of methamphetamine brought in for testing at its Ripon crime lab had disappeared.

2010 – A San Francisco lab technician was accused of stealing cocaine from the city’s crime lab. A few months later, the crime lab’s drug section was shut down.

7/2009 – Faced with allegations that one of their technicians had mixed up DNA test tubes, the San Francisco crime lab manager denied any knowledge of the mix-up. An investigation by ASCLDL/LAB found that there was indeed a mix-up and all records pertaining to it had been destroyed. A month after the report was issued on the incident, ASCLDL/LAB reaccredited the SFPCDL for five years.

2008 – Analysts at the Los Angeles Police Department crime lab misidentified fingerprints in two burglary cases, leading to an analyst being fired, two supervisors being replaced and three other employees being suspended.

5/2006 – Mark Eastman, a technical reviewer at the Sacramento crime lab had entered a DNA sample that did not meet minimum standards into a law enforcement database and had not rechecked DNA results in other cases.  It is standard practice to conduct and document technical reviews of all case files and reports. A technical reviewer is an employee that is either currently or previously a qualified analyst in the methodology being reviewed and performs a technical review of that methodology.


3/2013 – A workplace investigation of the Laboratory Services Division of CDPHE was conducted based on allegations made by a former employee. The report that followed the investigation found that employees were not properly trained, blood-alcohol samples were not tested correctly in some cases, and there was pressure from supervisors for lab technicians to give testimony when they were not qualified to do so. The report also noted a bias in favor of helping prosecutors get convictions as oppose to seeking justice.

12/2009 – A crime lab in Colorado Springs found that hundreds of blood-alcohol tests were reported to show incorrect higher alcohol levels due to testing errors. At least nine defendants were falsely convicted. The chemist involved was fired, but the crime lab was unable to explain how the errors occurred.


8/2011 – Connecticut state crime lab lost accreditation from ASCLDL/LAB because of concerns relating to evidence control, quality assurance, and management. This led to a serious backlog of cases that have yet to be analyzed. 


2008 – John Preston, a retired Pennsylvania state trooper, gave fraudulent dog scent evidence in several cases in Florida. Preston was labeled a “total fraud” in an Arizona case, and Preston and his dogs had been completely discredited by 1987. Bill Dillon, who was convicted based upon Preston’s dog scent evidence, did not know that Preston had been discredited until 2006 and it was not until 2008 that Dillon was exonerated after spending 26 years in jail.


1/2012 – The Chicago crime lab found through an internal quality assurance check that one of their crime lab analysts had failed to meet the standards for fingerprint analysis. Around a dozen cases had to be put on hold while the fingerprints were reexamined.

2009 – Lavelle Davis was convicted of murder in 1997 with the primary evidence being lip prints found on a roll of duct tape that experts testified matched Davis’s lip prints. Nine years later when the circuit court ordered a new trial, new expert testimony stated that lip print comparison evidence is not accepted science. All charges were dropped in 2009.


2012 – A sheriff’s detective misidentified a fingerprint, leading to the conviction of an Indiana woman. After eight years in prison, she was exonerated. The detective continues to work at the sheriff’s department.


2013 – State chemist Sonja Farak has been accused of tampering with drug evidence, potentially affecting 60,000 samples in 34,000 cases.

2012 – Chemist Annie Dookhan has been accused of falsifying drug sample test results, forging paperwork and mixing up samples affecting at many as 34,000 cases. Since then, 325 defendants have been released and their cases have been put on hold while their lawyers challenge their convictions. Dookhan is believed to have been doing this for years. Dookhan pleaded guilty and in November 2013 was sentenced to three to five years in prison.


2011 – A former Detroit crime lab was abandoned with evidence left in the abandoned building for anyone to have access to. The lab, which closed in 2008, was investigated and it was discovered that the lab workers had been habitually sloppy and had high error rates.

3/2009 – A Michigan prosecutor stated that 147 cases in which people were incarcerated would have to be reinvestigated because of serious lapses at the Detroit police crime lab’s firearms unit, which was closed in 2008. Among the reasons cited for the massive reinvestigation:  the unit’s 10% error rate in ballistic testing, the possible contamination of evidence, and failure to verify that testing equipment was maintained correctly.


2012 – The St. Paul crime lab was discovered to have little oversight, “poor documentation of the testing process and an absence of standardized policies for multiple aspects of its work.” This included that they did not follow any written standard operating procedures and may have relied on equipment contaminated by illegal drugs. In particular, fingerprint evidence and drug samples are believed to be unreliable.


2012/2013 – Evidence suggests that Dr. Steven Hayne, a forensic pathologist, testified to help convict two innocent people, and possibly more. He is believed to have made numerous misrepresentations about his qualifications and given testimony on theories that are not accepted forensic science.

New York

12/2013 – A crime lab technician in the New York City medical examiner’s office was reported making several errors and overlooking crucial evidence in a number of cases. These errors included mislabeling samples with the victim’s name instead of the suspect’s name, overlooking stains on clothing of sexual assault cases, not testing stains that they did find, and possibly falsifying reports.

2/2011 – Nassau County’s crime lab failed to follow testing procedures and national crime lab standards, requiring that hundreds of cases be reexamined. Nassau County government officials closed the lab soon after discovering this.

5/2010 – A NYPD criminalist was found to have taken shortcuts in testing drugs leading to unreliable results. The criminalist under question tested a substance for cocaine, determined it was negative and instead of retesting the sample, she marked the substance as positive for cocaine, leading all of the samples she had tested to be questioned.

1/2010 – An Erie County lab chemist was fired after falsifying a report that she had conducted tests on a cocaine sample, when she did not actually perform the tests (i.e., “dry-labbing”).

12/2009 – A NY Inspector General report for Monroe and Erie Counties found problems with dry-labbing, weight discrepancies, and skipping vital steps in tests.

2007 – Two technicians were found to have been lying about drug evidence; specifically they were dry-labbing and writing reports on tests they had never done.

North Carolina

2010 – Lab workers were found to have failed to turn over potentially exculpatory evidence, including in death penalty cases. It was also discovered that lab technicians had an unfair bias towards prosecutors, leading to false or misleading test results that supported the prosecution’s theories. The investigation of the SBI blood serology unit yielded a total of 229 cases of misrepresentation of blood serology. Of the 229 cases, seven persons had been executed, others were on death row, and some had died in jail.

2011 – State investigative officials found approximately 70 cases in which analysts did not report additional tests and results to prosecutors. These were discovered after the first investigation in 2010. Some of these cases involved the analysis of bodily fluid, including semen and urine.


2008 – Experts testified that the accused’s palm print had been made in the victim’s blood on a wall where the murder occurred. At retrial, it was discovered that the palm print had not been made in blood and the expert testimony was false.


2012 – Oregon must review several cases after investigating the handwriting unit and finding mistakes by their analysts.


5/2012 – Philadelphia Police Department crime lab technicians flunked a routine test given in order to keep their accreditation. This could potentially bring hundreds of cases back to the courtroom.

South Carolina

8/2014 – The sole employee of Columbia's crime lab was suspended after a defense attorney found that the employee had falsified records regarding the weight of cocaine in a case. As the city's only drug analyst, police and prosecutors are now analyzing hundreds of cases in which the analyst conducted drug tests. 


4/2008 – A Tennessee police officer resigned after being accused of falsifying records in order to cover up a botched ballistics test. The ballistics unit was shut down and two of the officers working in the unit were found to be unqualified.


1/2014 - The Texas Forensic Science Commission will be reviewing all state criminal convictions that include testimony on microscopic hair analysis. This comes after the announcement by the FBI and DOJ that federal hair comparison analysis was found to be unreliable. Many of the Texas' hair examiners were trained by the FBI. 

2012 – 26 cases were under review this past October in Texas because of discredited investigative techniques and the use of outdated science related to arson to convict suspects.

2012 – The drug testing program in the Harris County probation office conducted faulty urinalysis tests, sending innocent probationers back to jail.

06/2010 – A report on the arson investigation that led to Cameron Willingham’s execution found that investigators had relied on “flawed science.”

2009 - Fort Bend Deputy Sherriff Keith Pickett helped put several individuals behind bars based almost solely on Pikett’s testimony and dog scent lineups. Three individuals were cleared of all charges after others came forward and confessed to the crime or DNA evidence was found to vindicate the individual.

11/2009 – An audit of the Houston Police Department crime lab’s fingerprint unit found irregularities in over half of the 548 cases reviewed.

6/2009 – the Houston Police Department Crime Lab fabricated evidence used to convict George Rodriguez, who served 18 years in prison before being released.

1/2008 – The head of the Houston crime lab’s DNA division, Vanessa Nelson, was forced to resign after she was found helping DNA technicians cheat on proficiency exams. After resigning, Nelson was hired by the Texas Department of Public Safety to direct the agency’s DNA lab.


2008 - A toxicology lab manager at the Washington State Patrol crime lab was accused of falsely claiming she had verified solutions used in breath-alcohol testing.


08/2009 – A chemistry supervisor at the Wisconsin state lab failed to obtain peer reviews on 27 toxicology cases involving drugs. Upon review, only 5 cases met the required standards while half of the 27 need to be corrected.

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