MANILA, Philippines -- The son of Dr. Francisco Cruz, who took suspected hazing victim Cris Anthony Mendez to a hospital where he was later declared dead on arrival, did not appear at the National Bureau of Investigation (NBI) Wednesday.

Instead, Miguel Francisco, Cruz’s son, sent two lawyers who submitted to the bureau a letter in which he invoked his right to remain silent.

Cruz earlier asked NBI officials to give his son, who is nicknamed "Mico," up to Wednesday to present himself to the bureau.

"[We] advised our client to invoke his right to remain silent in connection with the reported ‘hazing initiation,’ ‘mauling’ and death of Mr. Mendez pursuant to Article III Section 17 of the 1987 Constitution," lawyer Abdiel Dan Fajardo, Mico's lawyer, told the NBI.

Mico was reportedly the one who took Mendez to their house in Congressional Village, Project 8, Quezon City, before the latter was rushed by the older Cruz to the hospital.

Mico is believed to be a member of the Sigma Rho, a fraternity at the University of the Philippines, which, according to the police, conducted the initiation rites in which Mendez is suspected to have died.

"That's his right," said lawyer Romulo Asis, chief of the NBI Anti-Terrorism Division, referring to Mico's non-appearance. "But it doesn't mean we're facing a blank wall as far as our investigation is concerned. We have other means of gathering evidence which we think would strengthen our case against those we deemed responsible for Mendez's death."

The older Cruz appeared at the bureau last week and gave a sworn statement. The NBI, however, did not release any details about his statement.

Mendez was declared dead on arrival at the Veterans Memorial Medical Center (VMMC) on August 27. The findings of an autopsy report showed that he was beaten up badly because of numerous bruises all over his body.