Jiang Yuan carefully lifted the fingerprints from the threads, made a copy, and photographed them.
For the average trace examiner, extracting fingerprints from a round object is already quite challenging. It is akin to turning a curved surface into a flat one. Jiang Yuan once dealt with a cold case involving fingerprints on the crossbeam of a bicycle. Due to substandard extraction techniques, it made identification difficult.
Extracting fingerprints from threads was even more difficult, but fortunately, the threads were very fine. Although this could lead to the loss of key points, it would not turn the fingerprints into a 3D curved surface.
Jiang Yuan proceeded with caution, first taking photographs, then dusting with powder, lifting the prints, and photographing them again. The process was complicated and time-consuming, but once extracted and entered into the system, it would become a regular fingerprint, ready for normal comparison operations.