Senate President Franklin Drilon and Sen. John Osmeña, chairman of the Senate committee on government corporations and public enterprises that is currently investigating the Impsa project, said Datumanong’s statement clearing Perez was uncalled for.
"I believed it was an error for Secretary Datumanong to clear Secretary Perez," Drilon said.
As justice secretary, Drilon explained, Datumanong has the power to review resolutions of government prosecutors.
"Saying that Secretary Perez incurs no liability would tie the hands of the prosecutor in a case if a case is filed and he has prejudged (it)," Drilon said.
Before being elected as senator, Drilon served as justice secretary during the administration of President Corazon Aquino.
Osmeña, for his part, said it was not for Datumanong to decide whether Perez can be sued on the Impsa controversy since any graft case to be filed against Perez would fall under the jurisdiction of the Office of the Ombudsman and the Sandiganbayan.
On Wednesday, Datumanong rejected a suggestion made by Osmeña that Perez should be indicted for graft in the Impsa deal, saying his predecessor should not be faulted for doing his job.
"My belief is for rendering a legal responsibility and duty. You cannot be faulted because you are doing what the law requires you to do," Datumanong said.
He noted that Perez "is not going to be sued for the opinion, but he will be sued for other things," referring to other charges Perez is facing, such as allegations of bribery.
"But you must have proof," Datumanong added.
Perez, for his part, has repeatedly denied having issued the Impsa legal opinion hastily and lamented that he was not invited by Osmeña’s committee so that he could have shed light on many issues, foremost of which is the granting of the government guarantee.
He reiterated that neither the incumbent Arroyo administration nor that of Estrada had issued a sovereign guarantee.
Perez explained that the legal opinion he issued, four days after he took over as justice chief, was needed since there was a "substitution of parties" and transfer of rights from Impsa to CBK and its creditors.