Dhaka, Bangladesh (CNN) - Deep scars crisscross the frail body of a seven-year-old boy at the center of a criminal case that investigators say exposes “pure evil.”

His father pulled the boy’s pants down, wanting to show the injuries that fill him with rage and anguish. His son’s penis had nearly been cut off.

“They beat me. They said they would make me beg. They would kill me,” the boy said. “I threatened to tell my father and police on them. They cut my throat, they cut my belly, they cut my penis.”

They also bashed his skull with a brick.

Investigators say members of a criminal gang were trying to force the boy to become a beggar on the streets of Dhaka, Bangladesh’s capital.

The boy was slashed many times, his healed wounds now forming a large cross in scar tissue across a section of his chest and from his throat to his pelvis. Investigators with Bangladesh’s elite police force, the Rapid Action Battalion, say the gang members were trying to kill him because he refused to beg and would be able to identify them to the police.

But he survived, and he and his family have been placed in a witness protection program. The boy is now the star witness in a case that has exposed a criminal gang that, according to investigators, has snatched children off the streets, maimed them and sent them out to beg for money. It is a case depicted in the Oscar-winning movie “Slumdog Millionaire,” in which a child is kidnapped and blinded in order to increase sympathy from the public and bring money to gangs. Pity pays.

The boy’s father says it all began with an argument he had with a neighborhood tea seller over an unpaid bill. Investigators say the tea seller turned out to be a member of a neighborhood gang who then retaliated against the family. One of their children went missing.

“I was crying loudly and calling his name. Suddenly I heard him calling ‘mama,’” his mother recalled. “His hands and feet were tied. I could hardly recognize him because he was so stained with blood.”

His father fainted when he saw the boy’s injuries. But when the man went to file a complaint at the neighborhood police department, police refused to file charges, saying it was a neighborhood dispute.

Incensed, the father eventually found a human rights advocate and attorney, Alena Khan, who went to the hospital to see the boy and helped the family file a legal case.

“We have heard that some people involved are politicians. Even some journalists are involved. So we think it is a very dangerous situation. Even I myself have gotten threats twice," Khan said. "They are terrorists because this is not a small group.”

The petition led the court to order a full investigation by the elite police force and Rapid Action Battalion. Within weeks of the boy’s identification of the five men who allegedly tortured him, they were arrested, and two suspects confessed in front of TV cameras at a police news conference.

“Sometimes they kidnap the children and hold them captive for many days. After that they cut different body parts to prepare them for begging,” explained Mohammad Sohail, head of the media wing of the Rapid Action Battalion. The children are fed very little food and water, are hidden in large vessels for months and suffer from nutrition deficiency, he added.

The gang has also killed children and thrown their bodies into the river, Sohail said.

“This type of crime really touched the hearts of the people, including the law enforcement agencies. So our stand is very, very hard against this mafia group,” Sohail told CNN.

Human rights activist Khan says the 2010 case may well be the first case of its kind to expose a criminal gang for forcing children to beg.

The Bangladeshi government says the boy’s case is not a “general phenomenon” and that it is seriously looking into the case and others. The government said offenders will be punished.

It has since passed a law that would impose a jail sentence of up to three years on anyone caught forcing another person to beg. The government has also banned begging in Bangladesh, but human rights advocates complain that enforcement is lax.

Beggars can be seen on the streets, including crippled children roaming the intersections and walking between cars asking for money.

As for the boy who refused the gang’s orders and paid a terrible price, he is scared for his life but when asked how his tormentors should pay for their crimes, he speaks like a hardened police officer. “I want them hanged, I want them hanged, I demand they be hanged.”