How to find out whether an iPhone is stolen?

Before buying a used smartphone always check the phone for sale hasn't been stolen or blacklisted.

Smartphone theft, in particular the number of iPhones reported stolen has increased dramatically. There is a huge market for cheap iPhones on eBay and classified sites.

Once a smartphone has been reported stolen, it is permanently blacklisted or barred from use by all network providers in the same country. Once blacklisted, the IMEI Number is immediately banned. An IMEI number is unique to each device and can't be changed or jailbroken.

What to do if you bought a stolen phone: Ask for a refund.
Ask your bank or card provider if cover is available to give you a refund.

How to find if an iPhone was stolen: https://www.imei.info/iPhoneBlacklistCheck/

Remember the above checker doesn't guarantee it hasn't been stolen, only that it might not have been reported yet. Try also by calling Apple and giving them the IMEI.

How to find an iPhone's IMEI: Using the number pad type *#06# to obtain the mobiles unique number.

Before buying a used iPhone be sure to check it's good.