Kenyan media is reporting that the bodyguard of Deputy Chief Justice Philomena Mwilu has been rushed to a hospital in the capital, Nairobi, after being shot.
The circumstances surrounding the shooting are unclear but reports say that Ms Mwilu was not in the car at the time of the attack.
She was one of four Supreme Court judges who voted to annul President Uhuru Kenyatta's win in the August election.
A journalist with Kenya's NTV station has tweeted.
The Supreme Court is due to hear a case tomorrow, requesting the postponement of the presidential election re-run scheduled for Thursday.
