Attorney Avigdor Feldman, the last person to see Ben Zygier alive before he was found hanged in his cell in Ayalon Prison in 2010, said Tuesday on an Israeli radio show that the offenses committed by another inmate incarcerated under similar conditions at the same time as Zygier were much more severe.

Asked on 103FM about the kinds of offenses committed by the mysterious inmate, Feldman said, "without getting into the details, they are far more sensational, far more astounding and far more fascinating."

According to Feldman, "this affair points to far more severe failures than the ones committed by the defense establishment in Zygier's case. Regarding Zygier's case, the authorities that recruited him didn't understand who they were dealing with and weren't aware of his conduct. Okay - that's a failure. Prisoner X number two is an entirely different story - a horrible security breach. When I heard the story, as an Israeli citizen I was shocked, and the subject was completely silenced by lawyers who enjoy close ties with the establishment. Whoever opens this affair will be doing the country a great service."

Earlier Tuesday, Feldman compared the two cases on Army Radio: "One: they’re both Israelis. Two: They worked for a security agency of the highest level of secrecy. Three — and this is important — their activity points to a security failure that allowed the crime to be committed, secrets to be kept, or other deeds to be done,” Feldman said on “Boker Tov Yisrael” (Good morning Israel).

According to documents from the Central District Magistrate’s Court, another, anonymous prisoner was being held at Ayalon at the same time as Zygier, and was serving out his sentence under similar conditions.

Zygier, an alleged Mossad agent popularly known as "Prisoner X," was arrested in February 2010 and spent 10 months in the isolation cell of Block 15 before he apparently committed suicide in December 2010.

The second prisoner was being held in Block 13 at the same time, according to the court report. He had reportedly already been convicted (as opposed to being detained during proceedings). It is unclear whether that prisoner is still being held at Ayalon.

The report was included in an appendix to a transcript of the hearings and decisions in the Prisoner X case. Judge Daphna Blatman Kedrai, the Central District Magistrate’s Court president, permitted the publication of the documents in response to a petition by attorneys Tali Lieblich and Yaron Shalmi of the Lieblich-Moser law firm.

Though the first page of the appendix is missing, its content makes clear that it is the report of the inquiry into the causes of Zygier’s death conducted by police under the supervision of Blatman Kedrai and the District Attorney’s Office of the Central District. According to the documents, the investigation was conducted by a special team of the security department within the police’s Unit of International Crime Investigations.

The inquiry also addresses the case of the other anonymous prisoner in an effort to ascertain the usual procedure for handling prisoners of this sort.

“It’s important to note that the investigative material contains highly specific, long and detailed regulations,” an investigator said. These regulations were in effect “both for the previous inmate of Block 15,” the investigator said, referring to Yigal Amir, and “for the other inmate of Block 13."

But “the investigative material that was gathered shows that in everything that had to do with the treatment of [Zygier], uncharacteristically, no specific procedure was laid down and no order issued on the matter.” This finding is based on testimony from the head of the Ayalon Prison, the shift commander, the intelligence officer, operations officers and control-center personnel.

The appendix includes a list of Israel Prison Service employees who were questioned under caution.

The report evidently relied in part on information from the Israel Prison Service’s own internal investigation, which was headed by Col. Avraham Meron, who was then the deputy commander of the Maasiyahu Prison. Meron has since become the head of the intelligence-collecting unit of the Prison Service’s intelligence department.

On Army Radio Tuesday, Feldman also said he believed Zygier may have attempted suicide in an effort to get the prison staff's attention, hoping they would rescue him.

“I ask myself straightaway whether it’s conceivable that Zygier, who was aware that he was under surveillance all the time, attempted suicide with the intent of being saved at the last moment. It’s possible that Ben Zygier was convinced the entire time that the system, which kept him under such close watch, would save him at the last moment,” he said.

Open gallery view Mossad agent Ben Zygier: His suicide in an Israeli prison was concealed by a gag order. Credit: Handout

Open gallery view The isolation cell in which Ben Zygier, known as 'Prisoner X,' was incarcerated. Credit: Haaretz