AFP Commissioner Mick Keelty is now working the case of the missing ballot papers as he begins his inquiry into how the Australian Electoral Commission lost 1375 West Australian Senate votes.
Mr Keelty will have five AEC staff on-hand, with access to more help if needed.
He begins the investigation in Canberra with briefings from the AEC but will travel to Perth next week.
An interim report is to be delivered before the end of November.
The Electoral Commission will consider what actions it can take based on Mr Keelty's findings.
The AEC is also considering its options as it waits to learn if the WA Senate outcome it announced this week will be challenged in the Court of Disputed Returns.
The AEC announced the results for the WA Senate ballot on Monday, which then allows 40 days for a challenge.
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