Bolt cutters exhibit an action called pinching. The blades of the bolt cutters are aligned directly across from one another. When brought together against, for instance, a piece of wire, they pinch the wire, and when the blades close, the wire is severed. This differs from tools that are said to shear objects. Shearing tools have offset blades, so they do not directly close on one another but instead slide past one another, like scissors. If used to cut wire or plastic, it is pos- sible that markings from one or both blades will be left behind on the cut surface.
Use of knives, axes, or other sharp, single- bladed tools will result in a slicing action. Again, marks can be left on the surface of the object being cut. The examiner will need to observe both sides of the cutting implement to determine its use in the crime. Marks of this type can be found in slashed tires and cut wires. Despite what is sometimes seen on various crime dra- mas, these types of marks are rarely able to be compared to marks on bodies of murder victims, because of the elasticity of the skin.