Salahuddin, Libya (CNN) -- It's a harrowing story -- even by the standards of blood-soaked Libya.

Muneer Masoud Own, 33, who made a living doing manual labor, said forces loyal to longtime Libyan leader Moammar Gadhafi slaughtered nearly 150 prisoners as rebels closed in on Tripoli last week.

Charred bodies littered the ground around a warehouse -- roughly 30 feet by 45 feet -- where the detainees were kept. A volunteer who helped remove them, Bashir Own, estimated that he had seen about 150 bodies. He is not related to Muneer Own, who said he barely escaped an ordeal that started about a month ago.

In early August, Muneer Own said, he and his 30-year-old brother were walking toward their grandfather's home when pro-Gadhafi forces detained them for reasons that were not explained. He said they were handcuffed, blindfolded and put into a warehouse with about 60 others who ranged in age from 17 to 70.

Over the next 18 days, Gadhafi's forces kept bringing detainees, Own said. Soon, about 175 people were crammed inside the warehouse, near the headquarters of the Libyan military's 32nd Brigade -- a much-feared unit led by one of Gadhafi's sons, Khamis.

Own said he endured horror and deprivation in the warehouse.

"I don't know how I survived those moments. They were abusing us and beating us," Own said. "All I was thinking of was going home. I was dreaming of freedom."

In the three days before he made his escape even as others around him were killed, the detainees had no food or water, Own said. The warehouse filled with the stench of human waste.

Then, suddenly, Own and the others found a reason to hope: Guards said they would soon release everyone. It was all they talked about for a day or so.

Just before sunset on the promised day of release, guards opened the warehouse doors, Own said, but the door did not lead to freedom. He said the guards tossed a grenade into the warehouse and started shooting.

Dozens fell dead.

Own ran for his life. He said about two dozen others managed to escape, but he lost track of his brother in the chaos. He has not heard from his brother since that day, he said, and assumes that he did not survive.

When rebels finally took over the base and residents felt safe enough to approach the warehouse, all they found were charred remains. Volunteers said they pulled out at least 150 bodies, the majority of them unrecognizable.

In another corner of the lot, piles of dug-up earth teemed with maggots. More bodies were found there.

People found a handful of papers that could help identify the victims, but no one is sure. Many of the victims may remain unknown, their families left without answers to their fate.