Perez, however, refused to identify the new witnesses, saying it would only "make life more difficult for them," aside from pre-empting the government’s move in pursuing cases against the ousted leader.
So far, four Estrada allies  controversial businessman Mark Jimenez, former GSIS president and general manager Federico Pascual, former SSS chief Carlos Arellano and Belle executive William Ocier  have submitted sworn statements implicating Estrada in alleged ano-malous transactions.
Plastics king William Gatchalian, who is also being wooed to testify against Estrada, met with Perez yesterday afternoon.
The justice chief said he doesn’t know yet if the former presidential adviser on migrant workers is willing to help pin down the former leader on a string of corruption charges.
"What we will do is study the evidence first even without Gatchalian’s statement," he said.
Meanwhile, Estrada’s lawyer Rene Saguisag said the ousted president would appeal the two Supreme Court decisions that ruled he had effectively resigned the presidency and he was not entitled to immunity from criminal suit.
Saguisag said their appeal would be based on the reservations of four judges on his eligibility for criminal immunity.
"All we need is a little push to convert those votes" in Estrada’s favor, Saguisag said in a radio interview with news station dzMM.
The rulings had exposed Estrada to possible arrest, and the new government of President Arroyo has barred him from leaving the country and warned ten countries against granting him political asylum.
Corruption investigators are investigating at least eight cases against Estrada but the SC has stopped the government from making any criminal indictments before March 22, the deadline for Estrada to appeal the court rulings.
The 63-year-old former movie start was toppled in a military backed civilian uprising on Jan. 20.
Saguisag said his client would argue in his motion for reconsideration that "there was no resignation" and that he only agreed to leave Malacañang Palace to avoid possible bloodshed. "It’s like leaving a house which has caught fire," Saguisag said of the actions of his client, who insists that he is president on leave and that Arroyo is just acting president.
"Self preservation is the first law of mankind," Saguisag said.
He added that Estrada is preparing to name a panel of lawyers who will represent him in the criminal cases the government is preparing against him.
Saguisag said Estrada was set to determine yesterday afternoon who the lawyers and what their assignments would be in the criminal cases that are to be filed before the Sandiganbayan.