MANILA, Philippines - A law professor from the Ateneo Human Rights Center has agreed to join a Truth Commission tasked to investigate corruption scandals linked to former President and now Pampanga congresswoman Gloria Macapagal Arroyo.

Justice Secretary Leila de Lima said Atty. Carlos Medina's inclusion brings to 3 the identified members of the proposed 5-man commission.

President Benigno Aquino III earlier appointed former Chief Justice Hilario Davide Jr. to head the commission, while retired Supreme Court Associate Justice Romeo Callejo has also agreed to join the investigative body.

De Lima said she and Davide recommended Medina's inclusion in the group. She said she believes President Aquino will formally appoint Medina in the commission.

The Truth Commission is expected to investigate various anomalies linked to the past administration like the “Hello, Garci” scandal, the botched US$329-million NBN-ZTE telecommunications deal, and the P728-million fertilizer fund scam.

Minority lawmakers have asked the Supreme Court to quash the executive fiat that would be investigating the faults of the past administration, saying it is redundant, discriminatory and unconstitutional.

In a 55-page petition, the lawmakers also sought a stay order from the SC against Executive Order 1 that created the so-called Truth Commission.