While 3D printing has a dark side, it is also being used to help law enforcement agencies recreate detailed models of crime scenes, car crashes, footprints and fingerprints, as well as making architectural models for planning raids and for courtroom use.
Police departments worldwide use 3D printing
The Hong Kong Police Briefing Support Unit is using its own 3D printers to make crime scene models, which help them understand the crime and present cases in court. The unit also uses 3D printed models of buildings and streetscapes for counter-terrorism planning. Like many law enforcement agencies, the Hong Kong police have made such models for many years, but 3D printers do it faster, with greater accuracy.
3D printed crime scene models can also be used to help gather additional evidence. In 2013, a 3D printed model of a crime scene helped Japanese police gather thousands of possible case-related clues from local citizens.
In the case of the 2013 death of six-year old Ellie Butler in Sutton, England, forensic pathologists supported the homicide prosecution of her parents by presenting detailed replicas of Ellie’s severely damaged skull, which were 3D printed from CT scans of her remains.
In May 2015, detectives and prosecutors in Birmingham, England, used a combination of 3D scanning and 3D printing to obtain a conviction in the notorious “suitcase killing,” in which Lorenzo Simon was accused of murdering his tenant, Michael Spalding, dismembering the body with a saw and partially burning it, and sinking the parts in weighted suitcases in the Birmingham canal.
Using this technology, the West Midlands Police – with the help of the University of Warwick’s Manufacturing Group – were able to show that a piece of burned broken bone found in the suspect’s backyard was an exact mate for a piece of broken bone found in the suitcases.
Using high-resolution scans of nine pieces of damaged bone, the team displayed the pieces on a large screen for investigators to study, which protected the actual evidence from handling and potential damage or loss. The scans were then used to 3D print courtroom replicas of the bones in such detail that saw marks from the saw used to cut up the body were visible and the pieces fit together like a jigsaw puzzle. Lorenzo Simon got life in prison.
3D printing assisting U.S. investigations
In late 2016, the Greene County Ohio Sheriff’s Office partnered with Ohio State University to try to identify the remains of a woman found in the woods near Dayton. After all attempts to identify the victim from the badly decomposed remains had failed, the police turned to 3D printing. After CT scanning and 3D printing a model of the victim’s skull, the model was fleshed out with clay. Images of the model were then released to the public, which quickly led to the victim being positively identified. The police investigation then shifted into high gear, resulting in suspects being identified, arrested and charged a short time later.
New York State Police recently teamed with the State University of New York New Palz’s Hudson Valley Advanced Manufacturing Center to solve a 47-year old Jane Doe murder case. After the SUNY team 3D printed a replica of the victim’s skull, it was handed off to a forensic artist to recreate the victim’s face. Before this step was completed, the victim was identified by other means.
Students at the Richmond County School in North Carolina are learning forensic pathology with 3D scanners and printers. University of South Florida students and researchers, along with local police, are using 3D printing to help identify the victims in nine Florida cold cases, some of which are decades old.
Joe Mullins, a well-known forensic imaging expert, teamed up with 12 students from the University of South Florida’s Institute for Forensic Anthropology and Applied Science. After 3D printing replicas of the victims’ skulls from 3D scans, the students rebuilt the faces with clay, then sculpted the lips and inserted fake eyeballs. The finished replicas were displayed at a USF event called The Art of Forensics: Solving Florida’s Cold Cases, and published in the media, in hopes that viewers would identify the victims.
How 3D printing is advancing
As digital tools for 3D modeling faces from 3D scans of skulls improve, forensic researchers should eventually be able to create a digital model of the face, which can then be 3D printed. Clay modeling will be unnecessary.
If CT scans, which are noninvasive, can be made before remains and clothing are disturbed by forensic pathology procedures, such 3D data can be used to 3D print models that allow investigators to examine bone and bullet fragments outside wounds, and even to go inside wounds to inspect and measure bullet or knife tracks and trajectories in relation to entry points and surrounding tissue. Such models could be 3D printed life-sized, or in larger-than-life-size for easier examination.
As stated by Eugene Liscio, President of the International Association of Forensic and Security Metrology, “There is a special need for techniques that allow pathologies to be presented clearly in the courtroom…3D printed models offer real three-dimensionality as well as a haptic component, which make it easier for medical laymen to understand.”
Could 3D printing help unlock smartphones?
3D printers can also reproduce fingerprints and palms. In addition to printing life-sized or larger-than-life models for comparing fingerprints and palm prints in the lab or the courtroom, in 2016 Michigan State University Police worked with researchers at the university to 3D print fingerprints, to attempt to unlock an otherwise uncrackable Samsung Galaxy 6S smart phone. Using fingerprints taken in life from the smartphone owner – a homicide victim – the researchers 3D printed replicas of the owner’s fingertips and coated them with metallic particles to conduct the slight electrical current the phone needs to respond to the fingerprint. Ultimately, this attempt failed, but only because the fingerprints from which the replicas were 3D printed lacked sufficient detail. With better fingerprints, this is a promising technique for unlocking smartphones.
In later research, the same Michigan State team found that they could 3D print hands capable of bypassing fingerprint and hand scanners. Although the intended use of the 3D printed hands was to calibrate such scanners, the researchers soon realized that 3D printed hand replicas could be used to defeat such security devices. Printed from flexible material that simulates the texture and feel of human skin and coated with metallic particles, the 3D printed replicas can be worn like a glove to fool slap readers and contactless readers.
Accessing 3D Printers
Some law enforcement agencies, such as the UK’s West Yorkshire Police, are installing their own 3D printers to help solve crimes and to prosecute offenders. As the agency’s Crime Scene Surveying Supervisor, Daniel Sharp, said, the 3D printer enables “the judge and jury to hold the crime scene in their hands.”
A Florida company, 3D Printed Evidence, offers such services to the law enforcement community, converting data from MRIs, CT scans and 3D scanners into physical models.
Law enforcement agencies lacking the budget or the personnel to 3D print replicas of evidence can farm out the work to one of thousands of independent 3D printing fabricators (often called “service bureaus”), which operate like local machine shops, and to university 3D printing facilities. In the long term, law enforcement agencies will probably operate their own 3D printers and scanners.
Although illegal uses of 3D printing could be substantial, this disruptive technology can help solve crimes and convict perpetrators. Governments, law enforcement agencies and homeland security must learn the risks of 3D printing, plan accordingly, and use the technology to help prevent or solve crimes.