Five people have been arrested for keeping 15 poor people in captivity and selling their blood to private clinics in northern India to make money, police said Tuesday.

The victims, who were freed in a raid Sunday, were lured with promises of good jobs and forcibly kept in a home in Gorakhpur, a town about 250 kilometers (155 miles) southeast of Lucknow, the capital of Uttar Pradesh state, said police Inspector-General D.K. Chaudhary.

India's booming economy has grown by an average of about 8.5 percent per year over the past five years, but more than 300 million of its nearly 1.1 billion people still live on less than a US dollar a day. Many become victims of illegal scams.

The five were charged with illegal confinement of people and attempt to murder, Chaudhary said. If convicted, they could be jailed for up to 14 years.

Police failed to arrest the alleged kingpin of the racket during Sunday's raid, he said.

Two units of blood and a large number of empty pouches were seized from the house, Chaudhary said.

"Every day a hired pathologist would arrive and collect blood," Chaudhary said.

The ringleader allegedly made up to 50,000 rupees (US$1,250; €790) a day depending on demand, Chaudhary said.

"These people were kept in a small dingy room without a window. They were so weak that they could not stand. They were just reduced to skeletons," said Deepak Srivastava, the investigating police officer.

Ramesh Sahu, a graduate of Patna University in neighboring Bihar state, told police he was promised 200 rupees (US$5; euro3) per day for an eight-hour job, Srivastava said. He ended up in the group's custody.

Suresh Chandra, a doctor at the B.R.D. Medical College in Gorakhpur, said all the victims were anemic with very low hemoglobin levels.

Chaudhary said the racket had been going on for a year. Police were investigating the possible involvement of doctors at private nursing homes, he said.