| Sometimes forensic disciplines overlap and non-traditional methodologies are necessary to solve a case. We have been called upon to handle computer investigations involving microscopic surface and material examinations. It is not a common occurrence but the scratch marks and abrasions on connectors such as USB devices can be as unique as fingerprint patterns. Hardware devices installed in a computer including hard drives can sometimes be authenticated as original or replacement by a microscopic examination of the thread patterns in their screw mounting holes. Several examples of these and other non computer technology forensic traces are illustrated in the attached photographs. (use the Back Button in your Browser to return to this page after viewing the image files) 1. An unused screw hole on a hard drive casing. Note the symmetry and smoothness to the outer ring. 2 Another screw hole on the same hard drive as the previous picture but this one shows some markings of abrasion and usage. 3 An unused screw hole on a different hard drive casing with no markings of previous use. 4 Another screw hole on the same drive as the previous image showing some abrasion markings. The upper band of threads appears distended and there are markings on the surface ring indicating previous threading with a screw. Note the surface abrasion marks at the very bottom on the image adjacent to the hole. 5 A hard drive casing mount screw hole with signs of use including the hole surface ring and the adjacent surface area. In many cases where a railing or similar attachment is affixed by a mounting screw, markings will be created by both the screw and the railing itself. 6. Another hard drive casing with the distinctive markings of having been attached to another item. 7. This is the surface of a floppy disk that was inserted and removed from a drive containing stripped off label and adhesive remnants from a previous disk. The small orange flecks are the pieces of old label that were transferred to the current diskette. 8. Additional view of item above. 9, Distinctive striping marks made on a USB connectors from repeated insertion and removal. The typically unique patterns are evident after a single insertion and removal and achieve greater depth with frequency of use. 10. USB photo #2 11. USB photo #3 12. USB photo #4 13 USB photo #5 14. The write protect tab on a floppy diskette showing ink markings where the tab was pushed with a pen tip. 15. Floppy ink mark photo #2 16. Floppy ink mark photo #3 |
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| Computer Forensic Associates, Inc. Telephone (443)519-4055 E-Mail info@4nsic.org |
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