Gopal Kumar Goyal, Vikas Kumar, Pawan Kumar and Ganesh Kumar were arrested by the National Investigation Agency (NIA) Saturday in Bihar's Lakhisarai district in connection with the serial blasts.
Seven people, including a suspect in the seventh bomb explosion at the Patna railway station, were killed and nearly 100 injured in the bomb blasts ahead of a rally of the Bharatiya Janata Party's prime ministerial candidate Narendra Modi.
Hindu youths were arrested in Bihar in connection with the Patna serial blasts.
Activists say that since the blasts, all those arrested or detained from Bihar and Jharkhand have been termed without hesitation as terror suspects linked with the Indian Mujahideen. But in the case of the four Hindu youths, who were arrested on charges of financially helping terror suspects, they have just been called "hawala racketeers". This has raised many an eyebrow.
"It stunned me to see that there is a soft approach by police as well as other government agencies to term the four Hindus arrested as terror suspects in serial blasts case," said activist Aneesh Ankur. Ankur said it appears that there is a "communal mindset" among police and other agencies to describe a Muslim as terror suspect if arrested or detained in connection with a terror act.
Irshadul Haque, editor of Patna-based website naukarshahi.in, said: "All four (Hindus) are surely terror suspects as they were getting money from Pakistan's (intelligence agency) ISI and distributing money for terror activities.
"If the NIA and police investigate without bias, it could provide more leads in the serial blasts and other terror activities," Haque said.
He said that four days after the serial blasts in Patna, he wrote a news story on what happened to a man named Pankaj, who was arrested by police from the Gandhi Maidan soon after the serial blasts.
"I have failed to understand why there is no news about Pankaj, who declared himself a BJP activist after being arrested by police," Haque said.
"Neither Bihar police nor NIA has come out with any explanation about Pankaj, whether he was released after interrogation or it was a case of mistaken identity," he said.
A senior police official said Indian Mujahideen may be using Hindu youths for terror activities. "It is a serious matter with the arrest of the four Hindu youths," he said.
An intelligence official, however, told IANS that neither police nor intelligence officials in Patna are sure that the four arrested Hindu youths were aware they were working for the Indian Mujahideen. According to police, the NIA detained six people and seized hundreds of bank passbooks, ATM cards and other documents in Lakhisarai, about 150 km from Patna.
Four of the detained were in touch with people in Pakistan through mobile phones, the intelligence official told IANS, not wishing to be identified.
He said Pakistan's Inter-Services Intelligence (ISI) may be behind the transfer of money for Indian Mujahideen operations.
"Four of the six, in the age group of 20 to 25, were sent to jail on charges of providing financial help to terror suspects after they were produced in court," the official said.
The NIA also suspects that those detained have links with terrorists in and outside the country.
"The NIA is scanning their mobile phone details to ascertain their connection with people based in Pakistan and other countries," police said.
Police sources said the NIA is likely to conduct raids in some places in neighbouring Jharkhand and in Karnataka in the coming days.
In the last few days, the NIA conducted raids at several places in Bihar in search of suspects involved in the serial blasts.