A room at Evin Prison damaged by Israeli airstrikes.

Authorities at Tehran’s Evin Prison were still attending to the dead and wounded on the evening of June 23 when one of the highest-profile inmates held there, Swedish-Iranian scientist Ahmadreza Djalali, called his wife to tell her he was safe.

Hours earlier, Israeli airstrikes hit the sprawling compound that holds thousands of detainees, many of them political prisoners. The destruction and damage was so extensive—far more than outside observers initially realized—that the prisoners were being transferred elsewhere, he told her in a brief phone call.

She hasn’t heard from him since. With reports that security services are moving quickly to round up and execute alleged spies, her fear was that Djalali, sentenced to death on espionage charges, could soon face a similar fate.

“We don’t know where he is,” his wife, Vida Mehrannia, said in a phone interview from Sweden. “I am so worried about his situation.”

Swedish-Iranian scientist Ahmadreza Djalali

Israel struck the prison as part of a wave of strikes that Defense Minister Israel Katz said targeted elements of Iranian state oppression, also including what he said were headquarters for the paramilitary Basij force.

The attack turned out to be among the deadliest of the 12-day war. At least 80 were killed, including family members visiting prisoners and locals living nearby, according to Iranian state media, which said more than 900 were killed during the war overall.

Human Rights Activists in Iran, a nongovernmental organization that gathers data from official sources and other contacts, also reported hundreds dead from the Israeli campaign and said it had identified 47 of the people killed at Evin.

The prisoners, male and female, were transferred to facilities that are more crowded and even less sanitary than Evin, according to several accounts shared by prisoners, their relatives and rights groups.

The Israeli military and the prime minister’s office declined to comment on the Evin attack and death toll. Iran’s mission to the United Nations didn’t respond to a request for comment.

The Israeli campaign sparked a wider crackdown by Iran’s clerical leadership, which is seeking to stamp out any real or perceived threats to its control. Security forces have detained more than 1,000 people accused of spying for Israel or other political crimes since the start of Israel’s bombing campaign on June 13, rights group Amnesty International said.

At least six men accused of espionage have been executed since the air campaign began, according to Iranian state media.

Damaged vehicles beside the wall of Evin Prison, several days after an Israeli airstrike.

Djalali, a physician and academic who specialized in disaster medicine, was detained in April 2016 while traveling to Tehran for a work trip. He was sentenced to death in 2017 on charges of spying for Israel after a trial that relied on confessions made under torture.

Djalali denies the accusation against him. European governments and rights groups have repeatedly called for his release. The European Parliament called on Iran last month to release Djalali and abolish the death penalty. Iran has also held people for use in prisoner swaps.

“On one hand, they are keeping Djalali as a bargaining chip,” said Saeid Golkar, an expert on Iran’s security apparatus at the University of Tennessee at Chattanooga. “But I’m very worried, because he already has a death sentence over him. In this atmosphere, he is the easiest target. It would be easy to get rid of him.”

Djalali was among the eight people on death row in Evin for charges related to spying, according to Amnesty. The prisoners’ supporters worry that those sentences could soon be carried out. Iran’s parliament is working on a bill that would impose harsher penalties for espionage, including the death sentence for collaborating with Israel.

“Israel’s bombing only worsened the situation for political dissidents,” said Tina Marinari, campaign coordinator for the Middle East at Amnesty.

The Israeli military attacked Evin Prison around midday. The airstrikes hit locations including the prison’s main entrance, the visiting room, the infirmary and a prison ward, according to Iranian state media, observations that prisoners relayed in phone calls with relatives or supporters, and rights groups. Images showed gaping holes in ceilings, piles of debris, shattered windows and broken hospital beds.

Around 25 bodies were pulled out of the infirmary alone, according to an account by two political prisoners who were there, Abolfazl Ghadyani and Mehdi Mahmoudian, that was circulated by a relative. They also said dozens of conscripted soldiers were killed.

Damage to Evin Prison’s hospital after Israeli airstrikes.

As night fell, inmates were shackled in pairs and loaded onto buses with whatever belongings they could carry, from clothes to food to larger objects such as refrigerators. Around 70 women were transferred to Qarchak Prison, where they shared two rooms and two bathrooms between them, according to Amnesty. Some 180 men were sent to Greater Tehran Central Penitentiary, commonly known as Fashafouyeh Prison.

Both prisons are crammed, hot and lack basic facilities such as access to clean drinking water and enough beds for everyone, according to statements by several prisoners circulated by their supporters and rights groups. Many inmates were transferred from Evin in such a hurry they weren’t able to carry their medication.

Kurdish activist Varisheh Moradi and two other female political prisoners now in Qarchak described filthy, grime-covered walls and beds “the size of coffins.”

“Although we are in worse conditions than before the transfer,” the three prisoners said in a letter shared by activists and rights groups, “the current conditions will not hinder our fight.”

Fashafouyeh Prison is no better. The air is suffocating, and the beds are infested with bedbugs.

“This prison cannot absorb its own inmates, let alone new arrivals,” Reza Khandan, an imprisoned Iranian human rights activist, said in a recorded phone call distributed through his Instagram account and shared by rights groups. “The hygiene and health situation is catastrophic.”

Djalali, the Swedish-Iranian dual national, was transferred to Fashafouyeh along with other male prisoners on the night of June 23, according to Ghadyani and Mahmoudian, who saw him there.

“However, immediately after entering the prison, he was hastily separated from the others and transferred to an unknown location,” they said.

Djalali’s wife still didn’t know his whereabouts.