question: how do forensic investigators find new forensic evidence years after the crime?
comment: Because technology is ever increasing, allowing us to pull DNA off of things that we couldn't before and to detect and trace other things that we could before. It's not the evidence is new, it's just that technology lets us discover more from it.
passages: During the analysis phase an investigator recovers evidence material using a number of different methodologies and tools. In 2002, an article in the "International Journal of Digital Evidence" referred to this step as "an in-depth systematic search of evidence related to the suspected crime." In 2006, forensics researcher Brian Carrier described an "intuitive procedure" in which obvious evidence is first identified and then "exhaustive searches are conducted to start filling in the holes."
   FA begins each case by conducting research from a range of sources, including: site visits, lidar scanning, photogrammetry and ground-penetrating radar, as well as the use of digital models to locate and synchronize source materials in space and time.
   Section::::Current issues.:Cold cases.
  
  With the considerable amount of advances in DNA analysis, old, open cases that still have intact evidence can be examined for biological evidence. New profiles are uploaded to CODIS everyday so the base population to search and compare to increases. Biological testing for cold cases, specifically homicides, encounter similar roadblocks as the SAKs - lack of funds or the DNA samples have not been properly stored thus too much degradation has occurred for viable analyses.
  
  Section::::Popular culture.
   One aspect is the analysis of trace evidence such as skid marks on exposed surfaces, where contact between dissimilar materials leaves material traces of one left on the other. Provided the traces can be analyzed successfully, then an accident or crime can often be reconstructed.
  
  Section::::Methods of analysis.
   After acquisition the contents of (the HDD) image files are analysed to identify evidence that either supports or contradicts a hypothesis or for signs of tampering (to hide data). In 2002 the "International Journal of Digital Evidence" referred to this stage as "an in-depth systematic search of evidence related to the suspected crime". By contrast Brian Carrier, in 2006, describes a more "intuitive procedure" in which obvious evidence is first identified after which "exhaustive searches are conducted to start filling in the holes"
   During the analysis an investigator usually recovers evidence material using a number of different methodologies (and tools), often beginning with recovery of deleted material. Examiners use specialist tools (EnCase, ILOOKIX, FTK, etc.) to aid with viewing and recovering data. The type of data recovered varies depending on the investigation, but examples include email, chat logs, images, internet history or documents. The data can be recovered from accessible disk space, deleted (unallocated) space or from within operating system cache files.
   Various types of techniques are used to recover evidence, usually involving some form of keyword searching within the acquired image file, either to identify matches to relevant phrases or to filter out known file types. Certain files (such as graphic images) have a specific set of bytes which identify the start and end of a file. If identified, a deleted file can be reconstructed. Many forensic tools use hash signatures to identify notable files or to exclude known (benign) files; acquired data is hashed and compared to pre-compiled lists such as the "Reference Data Set" (RDS) from the National Software Reference Library
   In forensic science, there are three areas of importance in finding the answers and determining the components of a crime scene: (1) specific incident reconstruction, (2) event reconstruction, and (3) physical evidence reconstruction. Specific incident reconstruction deals with road traffic accidents, bombings, homicides, and accidents of any severity. Event reconstruction looks at connections between evidence, sequence of events, and identity of those involved. Physical evidence reconstruction focuses on such items as firearms, blood traces, glass fragments, and any other objects that can be stripped for DNA analysis.
  
  Section::::Expertise.
   Forensic science is used by various other organizations to clarify the fate and whereabouts of persons who have gone missing. Examples include the NGO Argentine Forensic Anthropology Team, working to clarify the fate of people who disappeared during the period of the 1976–1983 military dictatorship. The International Commission on Missing Persons (ICMP) uses forensic science to find missing persons, for example after the conflicts in the Balkans.
   The actual process of analysis can vary between investigations, but common methodologies include conducting keyword searches across the digital media (within files as well as unallocated and slack space), recovering deleted files and extraction of registry information (for example to list user accounts, or attached USB devices).
  
  The evidence recovered is analysed to reconstruct events or actions and to reach conclusions, work that can often be performed by less specialised staff. When an investigation is complete the data is presented, usually in the form of a written report, in lay persons' terms.
  
  Section::::Application.
   The development of forensic science and the ability to now obtain genetic matching on minute samples of blood, skin, saliva, or hair has led to re-examining many cases. Evidence can now be uncovered that was scientifically impossible at the time of the original examination. Combined with the removal of the double jeopardy law in some places, this can allow cases to be reopened where prior trials have failed to produce sufficient evidence to convince a jury. People charged with serious crimes may be required to provide a sample of DNA for matching purposes. The most obvious defense to DNA matches obtained forensically is to claim that cross-contamination of evidence has occurred. This has resulted in meticulous strict handling procedures with new cases of serious crime.
   BULLET::::- "Forensic excavation and recovery of known human remains": Complete forensic archaeological excavation, recovery and analysis of human remains from the chambers identified to date.
  
  BULLET::::- "Forensic excavation and recovery, and further evaluation/ excavation of other areas of potential burial/ interest": Complete forensic excavation and recovery of all human remains in memorial garden and any other targeted area, following geophysical survey, assessment of witness statements, historical records, etc.
   Forensic taphonomy is a relatively new field that has increased in popularity in the past 15 years. It is a subfield of forensic anthropology focusing specifically on how taphonomic forces have altered criminal evidence.
   More recently, the same progression of tool development has occurred for mobile devices; initially investigators accessed data directly on the device, but soon specialist tools such as XRY or Radio Tactics Aceso appeared.
  
  Section::::Forensic process.
   BULLET::::- On 21 April 2016, police in Windsor, Canada, released a Snapshot composite of the suspect responsible for the abduction and murder of Ljubica Topic in 1971. It was the first public release of a Snapshot composite outside of the United States and, at the time, the oldest case to which the technology had been applied.
  
  BULLET::::- On 11 May, the Loudoun County Sheriff’s Office in Virginia released a Snapshot composite of a suspect responsible for abducting and sexually assaulting a 9-year-old girl in 1987.
   Because of this case, DNA databases were developed. There is the national (FBI) and international databases as well as the European countries (ENFSI : European Network of Forensic Science Institutes). These searchable databases are used to match crime scene DNA profiles to those already in a database.
  
  Section::::History.:Maturation.
   At the 2017 American Academy of Forensic Sciences conference, Elizabeth Murray, an Ohio forensic anthropologist, met Colleen Fitzpatrick and Margaret Press, founders of the DNA Doe Project, who discussed what genetic genealogy techniques could do for this case. The victim's body had long since been buried, but a vial of blood had been held in a lab for 37 years. The vial had not been refrigerated, however, resulting in the DNA becoming highly degraded, with only 50–75% of markers remaining. With the help of Greg Magoon, a senior researcher at Aerodyne Research, they were able to upload this DNA data to GEDmatch.
   The police unit manager involved in the matter commented that the new evidence was only found because of scientific developments and developments in forensic approaches that had taken place since 1996 which allowed microscopic blood stains and hair fragments to be analysed for DNA and other microscopic evidence to be found and used forensically.
  
  Section::::Trials.:2011–2012 trial.
   Identifying skeletal remains is a very sensitive research subject at the farm. With a new age and generation, there has been a paradigm shift in methods to identify the entrails of victims. With innovations and adaptation to change, computers are able to identify properties of bone matter that has been buried years beginning at the Forensic Anthropology Data Bank founded in 1986 at the University of Texas, which houses thousands of detailed measurements of skeletons. This data provides strong evidence that shows differences in ethnic background from ancient times to present today. Along with the data bank, technological innovations have given researchers a computer tool called "FORDISC". This program is used to evaluate subtleties in a bone sample on a much smaller scale, which can confirm or challenge theories and/or conclusions drawn by investigators.
   Section::::Evidence collection.
  
  Evidence comes in many different forms such as guns, blood on knives, etc. It can be anything from a biological sample like blood, or everyday item like receipts or bank statements. Other types of evidence include: fibers, firearm residue, photographs or videos, and fingerprints. Forensic scientists analyze this evidence so they can come up with an explanation for why and how a crime occurred.
   Overturning a conviction after dozens of appeals and petitions have been denied is notoriously difficult, though prisoners have some options at their disposal. They can still attain freedom if legitimate innocence can be proven. The most common method is by using DNA evidence to disprove a crime that happened before DNA testing was a viable option. The Innocence Project, founded to exonerate those convicted wrongfully, has found more than 300 post-conviction DNA exonerations in the history of the United States. Attorneys can file a motion to introduce strong new evidence to the courts. Other common innocence efforts center on victim recantations if applicable.
   Section::::Recovery of footwear impression evidence.:3D Optical Surface Scanning.
  
  Footwear evidence can be recovered with use of 3D scanners.
  
  There are two types of 3D scanners used in forensics:
  
  BULLET::::- crime scene scanners able to capture a large overview map of the scene;
  
  BULLET::::- ‘close-up’ 3D scanners able to capture individual objects in high resolution and full colour.
   BULLET::::- On 16 May 2016, eve of the third anniversary of veteran John “Jack” Fay’s murder, the Warwick Rhode Island Police Department released a Snapshot composite produced using DNA taken from a hammer found near the crime scene. Police hoped the composite would generate fresh leads in a case that may have involved multiple assailants.
   To meet these demands, commercial tools appeared which allowed examiners to recover phone memory with minimal disruption and analyse it separately. Over time these commercial techniques have developed further and the recovery of deleted data from proprietary mobile devices has become possible with some specialist tools. Moreover, commercial tools have even automated much of the extraction process, rendering it possible even for minimally trained first responders—who currently are much more likely to encounter suspects with mobile devices in their possession, compared to computers—to perform basic extractions for triage and data preview purposes.
  
  Section::::Professional applications.
   Christena Stephens of the Llano Estacado Heritage Foundation is also writing a book on the Hunt case. At a time when forensic science was hardly known in Texas, Stephens has uncovered clues to solving the case, including tire tracks and black tennis shoes.
  
  Section::::1973 Train Accident.
  
raw_presuppositions: New evidence is discovered years after a crime. There should be no undiscovered forensic evidence years after a crime.
raw_corrections: New evidence is not found years after a crime, but new technology allows discovery from the same evidence.  Technology is ever increasing, allowing us to pull DNA off of things that we couldn't before.