- The US and Italy brought an extradition treaty into force in 1984
- It obliges each country to extradite anyone charged with or convicted of an extraditable offence by a jail sentence of more than one year
- In this case, Italy must give the US specific documents to show they have "probable cause to believe" that Meredith Kercher was murdered, and Miss Knox committed the offence
More top news
An 'unarmed' black man, who was reported to be mentally ill, has been shot dead by police in California after his sister called for help.
"Rubble fell in on intensive care patients" in the early hours of Wednesday, medics said.
The inquiry's most senior lawyer is said to be considering stepping down after disagreeing with its chairwoman Alexis Jay over its future.