For over a decade, tens of thousands of people living in Syria would disappear without explanation. They were picked up off the street. Plucked from university classes. Yanked out of stores as they bought groceries, and from taxis on their way home from work.

Relatives were never told what had happened — but they knew. Many of the disappeared had been thrown into President Bashar al-Assad’s vast network of prisons, where they were tortured and killed on an industrial scale.

Now, with the overthrow of the Assad regime, families of missing Syrians are hoping that they may be reunited with loved ones, or at least learn what happened to them.

On Sunday, they rushed to one of the most notorious prisons in Syria, Sednaya, in search of news. Then on Tuesday, hundreds descended onto the morgue at a hospital in Damascus, where 38 bodies discovered at the prison had been taken.

Some displayed photos of missing relatives, asking if anyone recognized them.

In desperation, some forced open the steel doors of the mortuary refrigerators, yanking out large drawers and pulling off the blankets and tarps covering the bodies.

Others clambered to get inside the room where forensic examiners were taking photos of the dead and cataloging them. The conditions of many of the bodies offered silent testimony to the brutality the prisoners had endured.

In the days since rebels toppled Mr. al-Assad’s government and freed prisoners held across the country, thousands of Syrians have flooded into Sednaya prison.

The prison sits atop a hill on the outskirts of Damascus, surrounded by barbed wire and fields riddled with land mines. Rebels who entered the prison complex on Saturday night set the fields ablaze in an effort to set off the mines.

Within hours, hundreds of prisoners were walking out of Sednaya’s gates, stunned. But many of the thousands of people converging on the prison complex looking for relatives and friends were devastated not to find them.

Rumors of secret cells three stories underground soon circulated, setting off a mad dash to free anyone who might still be imprisoned. For two days, rebels and rescue workers hammered away at concrete floors and tore them apart with excavators.

“I can see wires here! Where are they going? Is there a shaft here?” Tarek Abbas yelled from what appeared to be a prison electrical room.

Holding a shovel, he began tapping on the floor, trying to determine if any parts of it were hollow — perhaps a sign of hidden rooms.

Rescue workers digging in one cell urged family members crowding close to the bars to give them room to search. But in the end, they declared the rumors false: No secret cells were found.

The cells that only hours earlier had held the desperate and the disappeared told a tale of horror and deprivation.

Concrete floors were caked in layers of dirt, and a few blankets were strewed in rooms that one former prisoner said had contained dozens of people at a time.

As dusk began to fall, dozens of men gathered on a lawn outside the complex. Rebel fighters lay their guns on the dried earth. Civilians joined them, many carrying photos of lost loved ones in their jacket pockets.

It was a time for prayer.

As forensic examiners toiled inside the morgue at Al-Moujtahed Hospital, families outside waited for news, even if they dreaded it. They scoured a newly formed Telegram channel on which the medical workers were posting photos of the dead.

But most of the faces in the photos were too gaunt, the cheeks too sunken.

“How can we even recognize them?” one woman asked, as a man nearby scrolled through the pictures.

Gazing at photos of corpse after corpse, many were suddenly confronted with a reality they had long tried to keep out of mind.

They had imagined husbands, brothers and sons as they last saw them, as they appeared in the photos they kept in their phones and on social media. The people they were searching for were smiling, with cheeks flush with life and muscle on their bones.

Now, as they stood in the morgue’s courtyard, their memories were being overwritten by the images of ghostly corpses.

As the day dragged on, the crowd at the morgue grew larger — and more impatient. Throngs of people pushed and shoved, desperate to get into the mortuary refrigerator.

“Please,” one examiner pleaded. “Take a step back, take a step back.”

By early afternoon, the crowd had won.

People flooded into the mortuary cooler. They stepped over the feet of one corpse that lay across the doorway and tore open the tarps wrapped around the dozen others in the room. One woman shrieked at what she found.

Most of the bodies were emaciated, the skin hanging off their bones. The shoulders of one man was covered in the scars of puncture wounds. Another had a thick red scar around his neck — a rope burn, the examiners believed. Yet another man was missing his eyes.

“Our children are martyrs, our children are martyrs,” one woman screamed, stumbling out of the room.

Others left silently, blank stares on their faces and tears streaming down their cheeks.

“Our children are dead,” one woman yelled between sobs. “Our children, our children. They are dead.”