Security experts in the US and Britain are combing through the video of the murder of journalist James Foley as they try to identify the killer with a British accent.
It's thought software will be used to identify obvious characteristics in the voice, such as the pitch.
It'll then be matched against a database of those thought likely to be associated with the Islamic State group.
The US has continued airstrikes against the militant group in Iraq, despite a threat by I-S to murder another American reporter.
