This developed as the Office of the Ombudsman recommended a formal investigation on the allegations against Perez.
On the other hand, Malacañang said there is no need to suspend Perez over the bribery charge since no formal complaint has yet been filed.
NBI Director Reynaldo Wycoco said subpoenas duces tecum have been sent to Bulacan Rep. Wilfrido Villarama, Sen. Panfilo Lacson and Manila Rep. Mark Jimenez to substantiate their accusations against Perez.
Wycoco said although the three legislators could help speed up the NBI probe, the three could not be compelled to personally appear at NBI headquarters on Taft Avenue, Manila.
Villarama has tagged Perez as a "million-dollar man" for allegedly having received $2 million from Jimenez in exchange for various concessions.
For his part, Lacson claimed that the money actually came from an Argentinean power firm wanting to set up operations in the Philippines, which money was deposited in Coutts Bank in Hong Kong.
Jimenez, the adviser for Latin American affairs of the deposed Estrada administration, is the subject of an extradition process to the US where he is facing a number of criminal charges.
Wycoco said the NBI has already launched its inquiry on the alleged bribery based on a written order by Perez himself issued last Wednesday.
"I would like your office to check whether the remittance, which originated from Uruguay, came from the drug cartel in South America and being laundered in Asia," the order stated.
The NBI chief said he created a fact-finding team composed of the heads of five units of the agency to conduct the investigation.
Asked how he could conduct an impartial probe on his boss since the NBI operates under the umbrella of the justice department, Wycoco replied, "The proof of the pudding is in the eating."
In recommending the inquiry on Perez, Deputy Ombudsman Margarito Gervacio said "a crime of plunder may have been committed."
Assistant Ombudsman Ernesto Nocos admitted, however, that there has been no concrete evidence yet against Perez.
He also said Ombudsman Simeon Marcelo has yet to see Gervacio’s recommendation.
Press Secretary Ignacio Bunye told reporters at Malacañang that President Arroyo has not ordered a preventive suspension on Perez in connection with Villarama’s exposé.
"There is no basis for taking that action because the complainant (Villarama), as far as we are concerned, has not come up with definite information," Bunye said.
He added that a letter addressed to the Presidential Anti-Graft Commission (PAGC) "was quoting raw information from third party sources."
Bunye challenged Villarama to formally file his complaint before the PAGC "instead of grandstanding in the media." – With reports from Romel Bagares, Marichu Villanueva, Jess Diaz, Katherine Adraneda, Delon Porcalla