There is no such thing as a perfect crime, just a staged one! L.P.S Forensic Science There is no such thing as a perfect crime, just a staged one! -Myrna A. Velez

Steps in processing a crime First officer is responsible for securing and isolating the crime scene. Record the scene by taking pictures, writing notes, and drawing the crime scene. Conduct a systematic search for evidence. Collect and package physical evidence. Maintain the chain of custody.

First Officer on scene The first officer on scene has the responsibility for preserving and protecting the area as much as possible. Also the first officer on scene has to make sure that the victims or witnesses do not speak to each other.

Photography of the scene The most important rule for photographing is that nothing must be moved unless injured people are involved. Each crime scene should be photographed as completely as possible. As items of physical evidence are discovered they are photographed to show their position and location relative to the entire scene. This is also useful when videotaping.

Writing notes at the crime scene Note taking must be a constant activity throughout the processing of the crime scene. Notes must include a detailed written description of the scene with the location of items of physical evidence recovered. Tape-recording can also be used and can be advantageous.

Drawing Sketches of the crime scene There are 2 types of sketches: - Rough sketch: a draft representation of all the essential information and measurements at a crime scene. This sketch is drawn at the crime scene. - Finished sketch: A precise rendering of the crime scene, usually drawn to scale. There is also the computer sketch, that can be very helpful when dealing with a difficult crime scene.

Example of Rough Sketch

Example of Finished Sketch

Example of Computer Sketch

Conduct a systematic search for evidence There are 4 different kinds of systematic searches that can be used to search for evidence. They are: - The Grid Search Method - The Spiral Search Method - The Strip or Line Search Method - The Quadrant or Zone Search Method

Grid search

Spiral Search Method

Strip or line search method

Quadrant or zone search method

Collect and package physical evidence There are different types of packaging that can be used to package evidence. They are : - Manila Evidence Envelope - Metal Pillboxes - Sealable Plastic Evidence Bags

Fingerprints An impression on a surface of the curves formed by the ridges on a fingertip. When a crime scene is being processed there is always evidenced that needs to be checked for fingerprints. Fingerprints can be left on a surface just by the oils of your skin. For example: If you rub you nose and place your finger on a computer screen that is not on, you will see your fingerprint.

Fingerprints continued… Fingerprints are classified into groups so that they are easier to identify. The groups that they are classified into are: - Loops - Whorls - Arches. Remember: The proof is in the prints!

Whorls Between 25 and 35 percent of the patterns encountered consist of whorls. Plain whorls: As with any whorl there must be more than 1 valid delta or else it is a loop. Central Pocket Whorl: Consists of at least one recurving ridge with 2 deltas. Double Loop whorl: Consist of 3 separate and distinct shoulders and 2 deltas.

loops Loops constitute between 60 and 70 percent of the patterns encountered. Radial Loop: Is found on the left hand. Ulnar Loop: Is found on the right hand.

Arches Arches represent only about 5 percent of the fingerprint patterns encountered **Arches have no deltas** Plain arch: This pattern tends to just flow through the print with no significant changes. Tented Arch: It looks like a delta (three sides of the triangle).

The Future of Forensic Science! Law & Public Safety The Future of Forensic Science!