1. Physical evidence includes fingerprints, firearms, trace evidence, biological evidence, and documents which are collected using various techniques like powder or chemical processing, photography, or sealing in containers. 2. Testimonial evidence includes witness statements, videos, and audio recordings which are gathered through interviews. 3. Once collected, evidence is examined using specialized tools, chemicals, and analysis techniques in laboratories to identify suspects or reconstruct crimes. Proper collection and handling is important to avoid contamination.