Comelec Chairman Benjamin Abalos said even if they could obtain a copy of the original recordings detailing an alleged wiretapped phone conversation between Garcillano and President Arroyo, the tapes could not be used as evidence.
"An evidence illegally sourced cannot be used as evidence," he said.
"The Commission is still discussing how to proceed with the probe because we do not know which tape to begin (with), we do not know which of the tapes is genuine."
Abalos said Garcillano may have violated a special law in which there is no attempted or frustrated crime as stated in the Revised Penal Code.
"But if you will analyze the tapes it seems that the person is just bragging," he said.
"He was trying to impress upon people that he could do this or commit the commission for the matter, but in truth all the things he promised did not happen."
Abalos said he had instructed the Comelec’s law department to look into the possibility of using the tapes as a "reference," but not as evidence in an investigation of Garcillano.
The poll body will investigate whether Garcillano and other Comelec officials mentioned in the tapes were indeed involved in electoral fraud, he added.
Last week, Garcillano was reported to have fled the country for neighboring Singapore.
A text message circulating in many parts of the country said Garcillano took off from Subic Free-port between 7 and 8 p.m. aboard a Lear jet.
The Air Transportation Office in Metro Manila confirmed the plane pilot filed a flight plan and indicated he had two passengers. The names of the passengers were not listed in the flight manifest, the ATO added.
However, Immigration Commissioner Alipio Fernandez said it would be difficult for Garcillano to leave the country without having his passport stamped by the Bureau of Immigration.
"He would be asked to board the same flight back and the airline which flew him in would be fined," he said.
"Without any exit immigration stamp (on his passport) from his originating port, he would not even be allowed to enter another country," Fernandez added.
On the other hand, Garcillano’s passport cannot be canceled without a court order, according to the Department of Foreign Affairs (DFA).
Gilberto Asuque, DFA spokesman, said a passport embodies the holder’s right to travel as guaranteed under the Constitution.
However, a DFA official, who asked not to be named, said the DFA could cancel Garcillano’s passport if Malacañang and the Department of Justice posed no objection.
"The DFA will obey whatever instructions that will come from Malacañang. But on its own, it cannot make a move. It’s hard because this is a political issue."
The official said Garcillano will be automatically declared an undocumented national after his passport is canceled and he can be deported to the Philippines.
"Once his passport is declared void, the DFA will inform the country where he is and that makes him an undocumented national, and that (means) his travel documents are non-existent and not valid," the official said.
Garcillano holds an official and a regular passport, the official said.