 They said the police compromised the evidence by committing several mistakes when collecting it including occasionally not changing gloves between evidence items, using one swatch to collect blood from three drops of blood on the bronco dashboard, packaging the swatches of blood evidence using plastic bags, not paper bags as recommended, and storing them in a police van for up to seven hours unrefrigerated.This resulted in 100% of the "real killers" DNA being lost.They argued that Simpson's blood found on the evidence samples resulted from contamination in the LAPD crime lab with the reference blood in all but three exhibits.