Without oxygen connected, blood is a darker red color. Carbon monoxide, a potentially deadly gas, can also bind to heme , with a bond around 200 times stronger than that of oxygen.

Camm’s case is only one of many that have come under fire for their heavy reliance on bloodstain pattern analysis, a subfield of forensic science criticized in a report released by the National ...

Blood is always red, and veins look blue or green because the skin filters light wavelengths differently. Skip to main content. Open menu Close menu. Live Science. Search.