We study the dynamic fracture of thin layers of suspensions of non-Brownian rigid particles. The impact of a projectile triggers a liquid-to-solid transition and a hole opens in the layer. We show that the occurrence of fracture and the spatial and dynamic features of the cracks depend mostly on the thickness of the layer and the particle volume fraction. In contrast, the properties of the fractured material seem independent of volume fraction. Finally, we measure the velocity of the crack tip, from which we estimate an effective value of the shear modulus of the fractured material. DOI:10.1103/PhysRevLett.110.148304