No evidence has been found of any irregularities in the postal vote system in Aberdeen South.
Deputy returning officer Crawford Langley is heading the investigation
An investigation was launched after an "unusually large" number of people said they had requested postal votes but had not received them.
Deputy returning officer Crawford Langley said there was no evidence of any suspicious activity.
He was granted a sheriff's order after raising concerns about at least a dozen "abnormal" cases.
Mr Langley sought the order on Thursday morning in response to the number of people asking for postal votes when council records showed they had already been issued.
The new constituency of Aberdeen South consists of the old Aberdeen South constituency minus one ward, plus three wards from the old Aberdeen Central constituency.
The latest BBC figures suggest the seat has registered the highest number of postal votes within Scotland with 9,324 voters deciding to cast their ballot via mail.
The move is believed to have been prompted by 10 people turning up at polling stations to be told records showed they were postal voters.
They are thought to have told poll officials that while they had applied for postal votes, they had not received them.
Mr Langley said: "Possibilities are that it's all perfectly innocent and just coincidence. Alternatively, the votes may have gone missing.
"Or the third possibility is that people, knowing the difficulties that have arisen elsewhere, are testing how robust our systems are.
"I think by the action I have taken, we are showing that our systems are very robust."