"We heard her location was established," he told reporters in an interview.
Villa-Ignacio said that once Ricaforte is arrested, she would be brought back to the Philippines to face trial.
"There is a standing warrant for her arrest," he said.
The Philippines has not yet asked the United States for the extradition of Ricaforte, he added.
Villa-Ignacio said US authorities have traced the doctor of Ricaforte’s husband, Orestes Ricaforte, a former tourism undersecretary during the Estrada administration, who was said to be undergoing medical treatment or check-up.
"If you establish the whereabouts of the husband, the wife would not be far away," he said.
Villa-Ignacio said some of Estrada’s co-accused might be planning to enter into a plea bargain agreement with the government to avoid being convicted of plunder.
The crime of plunder carries a penalty of life imprisonment, he added.
Apart from Ricaforte, Estrada’s other co-accused who remain at large are Delia Rajas, Alma Alfaro and Eleuterio Tan.
Atong Ang has made a plea bargain agreement with the government, while Sen. Jinggoy Estrada is out on bail. Lawyer Edward Serapio remains in detention.
The Sandiganbayan had already ordered the prosecution and defense in the Estrada plunder trial to submit their memorandums on or before the deadline of May 25.
On May 25, the case will be considered as "submitted for decision."
A decision will be issued by the special division approximately 60 days after May 25, or sometime in July.
Comprising the special division are Justice Teresita Leonardo de Castro, chairman, and members Associate Justices Diosdado Peralta and Francisco Villaruz.
A hearing was supposed to be held yesterday, but both parties have only filed a manifestation.
In a one-page manifestation, the prosecution said: "In view of the admission of the additional exhibits identified, presented and marked by the prosecution during the presentation of the defense witnesses, misconstrued by the defense as rebuttal evidence, the prosecution has decided not to present any rebuttal witness and will just submit a memorandum as directed in the resolution of this Court April 19, 2007."
The manifestation was signed by Villa-Ignacio, Deputy Special Prosecutor Robert Kallos, acting director Raymundo Olaguer of
Prosecution Bureau I, and John Turalba, acting director, Prosecution Bureau X.
"We are confident that within 60 days or less a decision can be issued by the Sandiganbayan," said Villa-Ignacio.
In its manifestation, the defense said the accused’s lawyers could not attend the hearing because of earlier scheduled hearings in
Manila and Las Piñas during the same day.