Administration Sen. Miriam Defensor Santiago tagged Tuesday a “notorious Cabinet member’’ for allegedly being behind a death threat she received and a disqualification case filed to stop her from seeking another six-year term in the 24-member Senate in the 2010 national election, all taking place last Monday.

Santiago said she would name the Cabinet member when the Senate resumes regular session on Jan. 18 where “with my parliamentary immunity, media can freely identify him without facing libel charges.”

The feisty senator said she received a death threat by phone while in her Quezon city residence last Monday, at the same time that her Quezon city office received a copy of a “scurrilous’’ petition filed with the Commission on Elections (Comelec) seeking her disqualification from the senatorial race.

A lawyer, Nombraan Pangcoga, filed the petition seeking to disqualify her for alleged “severe mental disorder’’ and for her alleged “deliberate failure” to fully disclose her wealth and business interests.

“She purchased a lot and built a titled mansion in La Vista Subdivision, Quezon City, at an estimated cost of P53 million,’’ Pangcoga claimed in his petition which was past the Dec. 6 deadline for the filing of disqualification cases.

“This is the handiwork of a PR firm hired by the Cabinet member to avenge himself against my pubic hearings, which showed he has stolen billions from public funds. The timing alone is meant to unnerve me just before Christmas,’’ Santiago said.

She said both the death threats and the disqualification case were filed the same day that the latest Pulse Asia survey results ranked her in the top four among senatorial candidates.

“An unknown male voice told me in Tagalog to stop speaking at rallies, or else something dire would happen to me,’’ she said during media interviews last Monday.

Santiago said she dared the caller “to shoot me (because) I don’t scare easy.”