Fig. 1: Association of forensic fragments and their fracture surface characteristics.

a Visual jigsaw match of the macroscopic crack trajectory at the typical examination scale. b Physical pattern match with comparative microscopy, with analyst focusing on macroscopic topological features. c 3D representation of a pair of fracture surfaces, showing detailed topographic features at the relevant comparison scale (∽20 grains), utilized in the current work. The fracture surface shows a biased orientation of the low-frequency texture in the direction of crack propagation, along the x-axis. d Height-height correlation variation with the size of the correlation window, showing the domain of the self-affine deformation and the deviation of the fracture surface characteristics at higher length scales ( >50–70 μm), which could be used for matching purposes. e For quantitative analysis of the fracture surface pairs, a series of aligned topographical images were taken, relative to a reference coordinate w.r.t. the right edge of the fractured article. A series of k = 9 topographical images with 75% overlap between successive images, rendering three fully independent sequel images on the fracture surface.