A rare Hebrew manuscript is at the center of an escalating legal battle between a US family and government institutions in Israel.

The manuscript – a 15th-century Bible from Corfu – has disappeared from the collection of the Ben-Zvi Institute, a government-funded academic body in Jerusalem academically affiliated with Hebrew University.

Earlier this month, an Israeli government watchdog informed the family that donated the manuscript to the institute that it saw no reason to  launch an investigation into its disappearance. A lawyer for the family members in New York and New Jersey termed that decision “scandalous” and promised further legal action.

The manuscript was entrusted to the institute on May 15, 1961, by David Silvera, whose family brought it from Aleppo, Syria. Silvera received two receipts — still in the family’s possession — from the institute, including one signed by Itzhak Ben-Zvi, the institute’s founder and Israel’s president at the time.

The receipts describe the manuscript in detail, confirm it was handed over, and promise it would be protected.

The manuscript, Ben-Zvi wrote, would be “kept under excellent guard along with the archived manuscripts kept in the Ben-Zvi Institute.”

The book’s whereabouts are currently unknown.

The manuscript’s disappearance was first revealed in May by this reporter in “The Aleppo Codex: A True Story of Obsession, Faith and the Pursuit of an Ancient Bible,” a book about the fate of the 10th-century Bible of that name.

In a prolonged correspondence with David Silvera’s descendants,  the Ben-Zvi Institute said it did not know where the manuscript was or how it went missing. A year-long search by the institute’s scholars turned up nothing, the institute said.

The family did not view that response as adequate, and filed a complaint earlier this year with Israel’s State Comptroller, an official government watchdog with the authority to investigate state institutions.

On July 12, the Comptroller’s office refused the Silvera family’s request for an investigation.

In a letter from that date given to The Times of Israel by the Silvera family, an official at the Comptroller’s office informed the family’s attorney that the Ben-Zvi Institute had taken the complaint seriously and had “taken the necessary reasonable measures to locate the manuscript.”

For that reason, the letter read, “we do not see a reason to continue our involvement.”

The Comptroller did not mention how the manuscript might have disappeared or where it might be found.

A spokesman for the Comptroller said the watchdog could only look into how the institute treated the family’s complaint, not investigate the disappearance. “We are not the police, and we do not have the tools to look for this manuscript,” Shlomo Raz said.

The disappearance of the Silvera manuscript appears to be linked to a broader affair — the disappearance of dozens of other valuable Hebrew manuscripts from the Ben-Zvi Institute’s library in the 1950s and 1960s. The absence of those manuscripts, never previously reported or publicly acknowledged, was first uncovered by this reporter in “The Aleppo Codex.”

Former officials at the institute have blamed a former director for the books’ disappearance. The institute has denied access to its files on the director’s time at the institute and on the circumstances of his departure.

The former director, Meir Benayahu, a prominent scholar and manuscript collector, died in 2009. His family has vehemently rejected the allegations, saying the officials are trying to conceal other instances of theft from the collection, and noting that no complaint has ever been filed with police.

Yaron Gaver, the Silvera family’s lawyer, said the Comptroller’s decision not to investigate was a “continuation of the scandalous behavior of government agencies in this case.”

“There is no logical explanation given here for the disappearance of a treasure of historical significance to the Jewish people,” Gaver said Wednesday.

Gaver sent a letter on Monday asking the watchdog to reconsider the decision.

“The mysterious disappearance of the manuscript, in my opinion, points to major negligence, in the best-case scenario for the institute, or, in a more uncomfortable scenario, to criminal activity,” he wrote.

Gaver said the family would take further action if the Comptroller did not investigate, including a possible police complaint or High Court of Justice appeal.

In a response Wednesday, the Ben-Zvi Institute noted that the Comptroller was “satisfied with our explanations.”

The Ben-Zvi Institute is currently part of a larger body, Yad Ben-Zvi, which was established in 1969, and “does not have liability for things that happened” before that date, the institute’s statement said.