Mwilu was among the judges who annulled President Uhuru Kenyatta’s initial election win in August 2017, leading to the controversial holding of a fresh vote.
She was due to be formally charged at a Nairobi magistrates’ court on Wednesday but High Court judge Chacha Mwita suspended the case until October 9 to hear a constitutional challenge brought by her lawyers.
Mwilu’s lead lawyer James Orengo, a prominent opposition figure and elected senator who played a key role in overturning last year’s election result, said the move against her was “an attack on the judiciary”.
“These charges have been brought not to secure justice but to secure the removal of the deputy chief justice from office,” he said before launching his legal challenge.
“There is no factual foundation for instituting these proceedings,” he said, insisting on her innocence.
After his initial victory was annulled, Kenyatta publicly warned that he would “fix the judiciary” and some judges subsequently faced threats and intimidation.
In October 2017, Mwilu’s bodyguard was shot dead the day before the Supreme Court was to hear a petition to postpone the re-run.
As a result, Mwilu did not attend the hearing and the lack of a quorum meant the election went ahead unchallenged.
“This is an intensified war on the Supreme Court,” Orengo said on Wednesday.
Mwilu was appointed to the Supreme Court in 2016 and shot into the limelight for her role in annulling Kenyatta’s first poll win.
She was accused on Tuesday of accepting money as a gift in dubious circumstances, failing to pay taxes and using false pretences to carry out a transaction involving an asset belonging to the Imperial Bank, which collapsed in 2015.
Mwilu appeared in court later that day and was released on bail of five million shillings ($50 000).
But Haji denied accusations the arrest was politically-motivated.
He said Mwilu was targeted as part of an ongoing crackdown against corruption, which has seen several high-ranking officials hauled into court, a rarity in graft-wracked Kenya whose citizens rarely see justice done.
“We are an independent institution and we are not being directed by anyone,” he said.
“This decision has not been taken lightly. The dignity and independence of the judiciary is dear to us.”