Khalil served as a foreign policy adviser to former prime minister Kevin Rudd back in 2007 and was also director of national security policy for the Coalition Provisional Authority in Iraq from 2003-04. He's running for Labor in the seat of Wills at the upcoming election, replacing retiring Labor MP Kelvin Thomson.

Khalil's name appears in two US diplomatic cables released by Wikileaks. According to the cables - one from 2007, the other from 2009 - Khalil conveyed information to the US embassy about the Rudd government's asylum seeker policy. The later cable lists Khalil as a "protected" source, which means his identity is not to be disclosed.

BuzzFeed News interviewed Khalil in his Melbourne campaign office on Wednesday, and asked him about his role as an informant for the US government. Khalil gave this explanation:

"Let me explain this to you. All these people running around with their conspiracy theories. I worked for a foreign policy adviser for Kevin Rudd. Part of it when you're an adviser, is that you meet with the French ambassador, the US ambassador, the Italian ambassador, you have conversations about policy and all the rest of it and then they write cables back. We do it. The Australian embassies and ambassador have conversations with the political parties and everything, this is a normal part of that work."