Police raided blood banks in Lucknow, the capital of Uttar Pradesh state, last month and seized about 60 pouches of blood ready for delivery to hospitals and private clinics, said Vinay Chandra, a senior police official. Each pouch contained a unit, or 3/4 of a pint (350 milliliters), of blood.

The seized samples had a low hemoglobin count and were unfit for human use, superintendent of Police Paresh Pandey said, adding he initially suspected animal blood had been mixed with human blood, but later discovered it was diluted with saline water.

Some of the blood samples tested positive for the hepatitis B and C viruses. Others had been diluted to make three units of blood from a single unit, Chandra said.

The men running the blood supply racket bought blood from professional donors who were paid as little as 25 rupees (50 U.S. cents) a unit. Diluted blood was sold to blood banks for 1,000 to 1,500 rupees (US$20-$30) a unit, Pandey said.

The suspected leader of the scam was a doctor who works at a state-run hospital, while three others were medical technicians employed at pathological laboratories in Lucknow, Chandra said. No details were available about the other two suspects.

Chandra said the men were arrested Sunday on charges of forgery and fraud, spreading infectious diseases, and for violating the Drug and Cosmetics Act. If found guilty, they could be sentenced to life terms in prison.

The fraud became known last month after a woman tested positive for hepatitis B after surgery at a Lucknow clinic. The virus was traced to a blood transfusion during the operation.

Lack of stringent legislation and oversight allows blood banks in India to supply untested blood to hospitals. Last week, media reports said at least four children in Rajasthan state were given blood donated by a man who later tested positive for HIV.