Was Western intelligence involved in the killing of Gaddafi's son Saif al-Islam?

Thousands of mourners in Libya turned out this week for the funeral of Muammar Gaddafi's son, Saif al-Islam.

The political reformer was assassinated when unidentified gunmen broke into his home in the country's north-west.

Who was behind his killing?

We discuss this with journalist and 'Going Underground' host Afshin Rattansi.