As far as his four children know, Juan Morantes has always been an upstanding soldier in the Colombian army. But the old military uniform he kept in his closet was for show. The truth was very different, and he prays the children never find out.

For the last nine years, the only army Morantes belonged to was an illegal one -- a paramilitary force that extorted, kidnapped and murdered its way to controlling large swaths of the countryside, according to personal accounts like his and reports by Colombian and foreign human rights groups.

"Sometimes the killing was for no reason," said Morantes, 35, who admitted to being an accomplice to brutality, but never a triggerman, in the United Self-Defense Forces of Colombia. . "I went along with it because if I didn't, it probably would have been me who ended up dead."

The group is a federation of paramilitary organizations that were formed in the 1980s to defend landowners against attacks by anti-government guerrillas. It fought alongside the army and gradually veered into drug trafficking and criminal violence. The organization agreed to a cease-fire in 2002, but was linked to numerous murders afterward. Two of its top leaders are wanted in the United States on drug charges.

Five months ago, Morantes said, he felt a noose tightening around him. His commander in the militia was shot and killed by a rival paramilitary gang, and he feared he might be next. So he approached a Colombian army colonel he knew and asked him about the government program that offered benefits to outlaws like him if they were willing to give the straight life a try.

The colonel persuaded him to move with his wife and two youngest children, ages 3 and 4, from their home in the northern state of Santander to a special group house for demobilized militiamen in this capital of 8 million. The older children, ages 12 and 14, stayed home with their grandmother. Morantes said he knew that if they glimpsed the family's new surroundings, they'd realize he wasn't really on an army training mission.

The family now shares a cramped bedroom in an unassuming house. A Winnie the Pooh cutout is taped above the adjoining twin beds where the family sleeps shoulder-to-shoulder. Stuffed on a shelf are the books Morantes is studying for a college degree in business. "I hope to buy some cattle and start a farm, maybe in partnership with other investors," said Morantes, who is using an assumed name in Bogota for protection. He agreed to be interviewed only if his real name was not used, his face was not photographed and the location of the house was not described.

The house's six other bedrooms are similarly furnished and inhabited by families going through the same process. There are 27 other such group homes in Bogota, run by private contractors for the Defense Ministry.

In the past three years, 7,960 members of illegal armed groups have joined the demobilization and reintegration program. They include ex-paramilitary fighters like Morantes and former members of anti-government guerrilla groups. The two sides have battled each other for years over land, political allegiances and, more recently, drug profits, killing tens of thousands of fighters and civilians in the process.

The demobilization program, developed by President Alvaro Uribe, has faced criticism from human rights groups, which object to exempting the fighters from punishment. But Uribe's public approval rating stands around 70 percent. Colombia's kidnapping and murder rates have fallen in the past two years to their lowest points in a decade, according to officials.

A law passed this summer is intended to encourage an additional 20,000 paramilitary fighters to surrender by the end of the year, with the promise of reduced jail sentences if they have committed serious crimes.

But the stepped-up effort has put stress on existing programs to house participants. . The government is now trying to move many participants into single-family apartments, long before their 18-month reintegration courses are complete. Morantes and his family are supposed to move in three weeks.

A more worrisome problem is security. Many of the men living in the group homes have enemies, including former associates on whom they have informed, which is why the locations are kept secret. On July 15, someone threw a grenade at one of the Bogota group houses, knocking down a wall. No one was seriously injured, but the attack sent a clear message.

Morantes said he sometimes has trouble sleeping, for fear of being hunted down by vengeful former militia associates. "But I don't let it drive me crazy," he said.

When he joined the paramilitary force at age 26, Morantes said, he did it for money. After a stint in the army, he was unable to find work. A paramilitary group active in Santander offered him about $100 a month, and he said he couldn't refuse. He said the group made its money from drugs, kidnapping, selling stolen goods and logging.

For a man of modest means, the demobilization program seemed a smart move. For 18 months, the government pays for housing, food, health care and education for the family, at a cost of about $12 a day. It also pays for secrets, providing participants with a list of amounts it will pay for specific information implicating former colleagues. The satellite telephone number of a commander, for example, fetches about $450.

"I have about $5,500 coming to me," Morantes said. "I was close to the command structure, so I have a lot of information."

His daily routine, however, is far more mundane. . He eats breakfast in a tile-floored common room filled with plastic tables and a wall-mounted television. He usually spends the morning studying, or trying to teach others in the program how to read and write.

The families spend much of their time in their rooms, but they are free to come and go as they please, as long as they don't venture beyond Bogota's limits. The children go to neighborhood schools and play together in the first-floor common room.

One recent afternoon, Morantes walked past the private security guard at the front entrance and sat down in the common room. His 4-year-old daughter, wearing a SpongeBob SquarePants T-shirt, jumped into his lap. "Can we go to the park?" she asked.

In some ways, the little girl's life has changed as much as her father's. She's been spending more time with him, but she misses the friends she had to leave behind.

On a shelf in the bedroom, she keeps a photo album full of memories of her life in Santander. There are snapshots of her on a couch, of her baby brother dressed up as a police officer, of a family vacation to Cali. There is nothing in the album to suggest the family's old life was anything but normal. Even though Morantes was often away from home for long periods, only his wife knew the real reason why.

Five years from now, Morantes said, he dreams that he and his family will be living in a new house, running a successful ranch. The children will tell friends that their father retired from the army. The two older ones, he said, are just beginning to think about what they want to do with their futures. "They are in a critical moment in their lives right now," he said. "I would prefer they don't discover the dark side of my past."

Luis Carlos Restrepo, right, Colombia's peace commissioner, received rifles from paramilitary fighters Saturday during a demobilization in Tilodiran, about 130 miles northeast of Bogota.