Photograph the splatter up close and record the location in notes, sketches, and logs.
All an expert to do on the scene analysis and reconstruction.
Minimize direct personal contact with blood. AIDS is the least of your worries from blood contact.
Collect all clothing from victim(s), suspect(s), and witness(es).
Collect the substrate for use in comparisons in a lab. Substrate is simply the material upon which the blood landed, like tile on the floor or wood walls.
Package each piece of evidence in its own well ventilated container. Wet blood should be collected in a glass vial to as close to 10 cc as possible. Dry blood should be moistened with distilled water on a cotton swab or gauze patch and placed in a glass container. All blood evidence should be refrigerated to minimize growth of molds and bacteria.