Chris Pincher, the disgraced former deputy chief whip, is at the center of an investigation that began last Thursday.
He is being examined for “actions causing significant damage to the reputation of the House as a whole, or of its members generally,” according to the parliament website.
Mr Pincher resigned in June over allegations he groped two men – with the resulting fallout widely attributed to bringing down Boris Johnson’s government.
Last month, it was reported that Mr Pincher would not be investigated by parliament’s watchdog.
The Independent Complaints and Grievance Scheme (ICGS) reportedly dropped the complaint because the alleged incident had happened outside of the parliamentary estate.
Mr Pincher was the Tory MP for Tamworth as Staffordshire but now sits as an independent in the Commons.