- 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
Cool and breezy for the time of year
The people behind the moving tribute marking 100 years since the Battle of the Somme were unknown - until now.
Gunmen have stormed a restaurant in Dhaka, Bangladesh, taking a number of hostages and opening fire at police. Here's what we know.