Why Knox Got an Extra Year in the Clink

The Amanda Knox trial has left a lot of unanswered questions, and some totally answerable ones. Slate’s Explainer feature tackles the latter:

• Why did Knox get 26 years, while Raffaele Sollecito only got 25? Knox got an extra year for falsely accusing an innocent man (she accused the bar owner early on in the investigation, but later said she did it under duress).

• Knox’s attorneys said the prosecution’s DNA evidence was contaminated and insufficient. Can DNA really produce a false match? Yes. It’s common for police or lab techs to accidentally transfer a few thousand picograms of DNA between items. The amounts found on the knife were so small that a US crime lab would have thrown out the results.
• Didn’t they scrub that knife with bleach? How was there any DNA? DNA’s pretty persistent. Even bleach will only remove it if you’re really, really thorough when cleaning.