MANILA, Philippines -- Swiss aid worker Andreas Notter was on the move with his Abu Sayyaf captors Saturday until suddenly, he found himself alone and free.

"Notter was walking with his captors when one of them would sit down, another would tie a shoelace and before he knew it he was all alone,'' Senator Richard Gordon said in a phone interview, on Sunday.

Gordon said this was how Notter recounted to colleagues at the International Committee of the Red Cross (ICRC) the day he walked to freedom after more than four months in captivity by the Abu Sayyaf.

"I think he was freed,'' Gordon said, after hearing Notter's account as told to him by Gwen Pang, deputy secretary general of the Philippine National Red Cross (PNRC).

"But whether [Notter] was freed or rescued is beside the point because we have one life again,'' said Gordon, who chairs the PNRC.

The senator commended the police and military for continuing to exert pressure on the Abu Sayyaf without endangering the lives of the hostages.

But like Notter, Gordon said he was concerned about the remaining ICRC hostage, Italian Eugenio Vagni, said to be ailing. Vagni is suffering from hernia and said to be having difficulty walking.

Earlier, the Abu Sayyaf released Filipino engineer Mary Jean Lacaba, who like Vagni and Notter were snatched by the al Qaeda-linked group in Jolo Island last January 15.

Gordon said Abu Sayyaf leader Albader Parad, with whom he had been in constant contact, had not called him up since Notter's release on Saturday.

Senator Rodolfo Biazon said on Sunday that Notter was released because, apparently, the Abu Sayyaf bandits believed they would be able to get whatever demands they would make from the government in exchange for the ailing Vagni.

"Maybe Vagni's medical condition would put a little more urgency to his release,'' Biazon said in a separate phone interview.

Senator Loren Legarda said that the release or recovery of Notter and Lacaba showed "that a smart policy of dealing with the kidnappers rather than a knee-jerk reaction of violence could work out well for the hostages.''

"Jean, Andres and Eugenio, who work for the International Committee of the Red Cross, deserve all our gratitude and help for risking their lives to do humanitarian work for less fortunate Filipinos,'' Legarda said in a statement.

She also expressed relief over AFP Chief Alexander Yano's statement that ?all non-violent mechanisms are being exhausted to ensure that this release of Vagni will happen at the soonest possible time.?

"So long as the Italian Eugenio Vagni is still in the hands of his kidnappers, the authorities should give priority to his release for humanitarian reasons,'' Legarda said.