UPDATE, 8.45am: Police are waiting for the analysis of forensic evidence to determine if an investigation into a threatening letter moves forward.
Police sources say they have no suspects and it's unlikely any charges will be laid with the evidence they currently have been provided and obtained.
It's understood that South West Coast MP Roma Britnell and staffer Jarrod Woolley's email accounts have been examined by investigators and they have no link to the email posted to Upper House MP Bev McArthur's office.
Thursday: Police are investigating whether a copy of an email threatening state MP Bev McArthur came from the office of neighbouring South West Coast MP Roma Britnell.
It is understood Ms Britnell has rejected the suggestion. A police source said she had initiated a complaint which led to the investigation.
It's understood the copy of the email, which was contained in a letter, has been provided to Warrnambool police and the Victorian Parliamentary Security Committee.
The letter was addressed to Mrs McArthur's employee Jennifer Lowe at her Port Fairy electoral office.
Sources said the email print out purported to be from Ms Britnell to one of her employees, Jarrod Woolley.
The email says Mrs McArthur and Mrs Lowe were problems and needed to be "taken out".
The email was allegedly sent in January, printed out in July and brought to the attention of police about July 12.
A police source said the Victorian Parliamentary Security Committee had decided to take no action.
The source said that experienced Detective Senior Constable Wayne Ryan, of the Warrnambool police crime investigation unit, was heading the inquiry.
A spokesman for Ms Britnell declined to comment although it is understood she has welcomed the investigation.
In a joint statement, Ms Britnell and Mrs McArthur confirmed Victoria Police was conducting an investigation and "both look forward to the conclusion of that investigation".
"As this matter is under active police investigation it would be inappropriate to make further comment," they said.
Even though they are both Liberal Party members, Ms Britnell and Mrs McArthur are seen as political rivals.
Mrs Lowe and Mr Woolley were also contacted for comment.
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