Ombudsman Conchita Carpio Morales said she stands by her indictment of former President Benigno "Noynoy" Aquino III in connection with the botched 2015 anti-terror raid in Maguindanao province that left 44 police commandos killed.

Morales responded to President Rodrigo Duterte's description of the case against Aquino as "silly." She said everyone was entitled to his or her opinion.

“That is his own opinion, the case is pending, so everybody is entitled to his own opinion,” Morales said Friday.

The Ombudsman earlier ordered Aquino charged for usurpation of authority and violation of the Anti-Graft and Corrupt Practices Act.

Also included in the charges were now-retired Philippine National Police (PNP) Director General Alan Purisima and the former chief of the police Special Action Force (SAF), now-retired Director Getulio Napeñas.

• READ: Aquino to face trial for Mamasapano carnage: Ombudsman

Aquino has appealed the indictment.

Morales reiterated that she goes by evidence when deciding whether to file cases against government officials.

“I am not listening to anybody, I go by evidence,” Morales said.

Morales has been criticized by the Volunteers Against Crime and Corruption for filing a seemingly watered-down case against Aquino. The group also called for her inhibition from the case.

“Bakit ako magi-inhibit? I am not a coward,” Morales said.

In an apparent show of exasperation, Morales said her job as top graft-buster of the country is not an easy job.

“Maraming bumabatikos sa akin, akala mo kung sino sila, kayo na maging Ombudsman, it’s a thankless job,” Morales said.

“The Ombudsman cannot be silenced, they can attempt to suppress the message but they cannot repress the messenger,” she told prosecutors attending a symposium.

Asked for clarification in her interview with the media, Morales did not specifically say who is repressing the Office of the Ombudsman.

“Marami ang nagsasabi mali ako ganito, ganyan, so I come up with a message pag tinitira pa rin ako, what did I say, you may attempt to repress the messenger but you cannot suppress the message,” Morales said.