KABUL, Afghanistan – The great escape from Sarposa prison began with a knocking beneath the floor.

A 25-year-old Afghan recounted in a telephone interview Wednesday how three inmates at the prison in the southern city of Kandahar were expecting the knock. When it came about 11:30 p.m. Sunday, they knew what to do.

They knocked back.

Moments later, the floor gave way to reveal their escape route: a 1,050-foot tunnel, complete with lights and ventilation.

The Afghan was referred to Los Angeles Times reporters by a Taliban spokesman. Although his account could not be independently verified, his description of events and circumstances that night matched information released by Afghan authorities.

The account provided a glimpse into how at least 488 inmates — more than a third of the prison population — made their dramatic escape in what the Taliban has hailed as a major victory. As of Wednesday, only 75 of the prisoners had been caught and two killed, Afghan officials said. The incident has provoked international outrage at Afghan security forces’ failure to protect the troubled prison, the site of previous insurgent attacks and escapes.

The Taliban fighter, who asked not to be identified, said he had served one year of a six-year sentence after he was captured during a fight with NATO forces. He had been visiting inmates elsewhere in the prison — the cells were left unlocked at night while guards stayed at the main gate, he said — when the man told him about the tunnel and urged him to share the plot with the other 20 inmates in his cell.

“Tonight is our escape night,” he said the man told him.

He stared into the mouth of the tunnel as armed insurgents emerged. Inside the tunnel, about 2 feet wide and 10 feet deep, insurgents had installed battery-powered lights about every 15 feet to guide those escaping on their way under guard towers and razor-wire-topped barrier walls, beneath a busy highway and around police checkpoints. Fresh air was piped in through a makeshift ventilation system that allowed inmates to travel along the tunnel for 4 hours.

The fleeing prisoners emerged in a mud house secured by Taliban organizers who the man said had planted land mines and set up ambush positions along escape routes nearby in case security forces discovered the tunnel before all the inmates had escaped from the prison’s political wing.

But guards failed to raise the alarm until after the inmates had cleared the tunnel and disappeared. No shots were fired. In fact, security forces had searched the house 2 months before without noticing the tunnel, Afghan officials later acknowledged.

Some inmates who reached the house caught rides in cars that were waiting outside, while others walked to a nearby village, the escapee said. Taliban forces did not strong-arm them, he said.

“They told us that we are free, we can go anywhere we want,” he said.

The escapee did not disclose where he was hiding or how he got there. But he said he had received help, and not just from the Taliban. “Many people in the city of Kandahar and also from surrounding villages helped us a lot,” he said. “People who didn’t even know us helped us with transportation and other things we needed.”

Contrary to the suspicions of some investigators, the man said inmates did not receive any help from Sarposa prison guards or other staff members in making their escape.

He rejected reports that some of his brethren had been recaptured and killed, and crowed about the escape as an undisputed victory for Taliban forces.

“Our operation embarrassed the Kandahar authorities, the foreigners and the central government. The government had no idea about our escape until we broke the news,” he said.

Taliban officials had claimed that among those who escaped were 106 commanders who could help lead future fights. With Afghanistan’s spring fighting season heating up, the man said he would willingly join them.

“My friends and I are ready to sacrifice ourselves in the fight against the foreigners.”