Sampling is due to begin at the home of a Borders man who is believed to have died of anthrax.
Pascal Norris died in July
Christopher Norris had lived at Black Lodge near Hawick.
Since suspicions behind the 50-year-old's death were announced two weeks ago, the remote property has been sealed off and under police guard.
The B6399 Hawick to Newcastleton road will be closed to all vehicles, pedestrians and livestock from 0900 BST to allow testing to take place.
The road may also be closed on Saturday, if necessary. Diversions will be in place via the A698 and A6088.
Mr Norris died in July from an infection believed to have been caused by the anthrax.