What are the three main groups of fingerprints found at crime scenes?

The three main groups of fingerprints found at crime scenes are plastic, patent, and latent.

Plastic fingerprints are impressions made in a soft material, such as wax, putty, or mud, which can capture the ridges of a finger. These impressions provide a three-dimensional representation of the fingerprint and are often very clear.

Patent fingerprints are those that are visible to the naked eye. They occur when a finger that has been in contact with a colored substance, such as ink, blood, or paint, then makes contact with a surface. This type of print can be immediately observed without any special processing.

Latent fingerprints are not visible and are the result of natural oils and sweat on the fingertips transferring to a surface. Since these prints are often invisible, they typically require special methods of development, such as dusting with powder or utilizing chemical techniques, to make them visible for analysis.

Understanding these categories is essential for crime scene analysis, as each type has its own recovery and processing techniques that can aid in a forensic investigation.