Can politicians be arrested?”
The answer is yes, absolutely. Or, the federal government can issue a “Writ of Quo Warranto” and remove the politician from office.
A “Writ of Quo Warranto” is a notice of demand, issued by a demandant to a respondent claiming a delegated power and filed with a court of competent jurisdiction, to hold a hearing within 3 to 20 days (depending on the distance of the respondent to the court) to present proof insufficient, or if the court to hold the hearing, the respondent must cease to exercise the power. If the power is to hold an office, he/she must vacate the office.