A Hindu fanatic sentenced to die for killing Australian missionary Graham Staines and his two young sons hoped to "bury" the spread of Christianity, the judge said.
In his written judgement released overnight following his sentencing Monday, Judge Mahendra Nath Pattnaik said he ordered Dara Singh to the gallows because the murder in the eastern Indian state of Orissa was the "rarest of the rare".
"He formed a militant group of local tribals to physically liquidate Staines on the belief that with Staines the spread of Christianity will be buried in the area," Pattnaik said.
He said he sentenced 12 others to life in prison but spared them the gallows because they were manipulated by Singh.
"The rest of the convicts who are gullible tribals blindly followed him (Singh)," the judge said.
Singh, an anti-conversion activist and radical vegetarian, was convicted of leading a mob which surrounded Staines' station wagon on January 23, 1999 as the missionary and his children slept in the remote village of Manoharpur.
The crowd chanted anti-Christian slogans and blocked the Australians' escape by brandishing axes before torching the car, burning to death Staines and his sons Philip, eight, and Timothy, 10.
"A crime has no religion. What sin (had) the two small boys committed?" the judge said.
"The Manoharpur massacre speaks loudly that humanity is not yet fully civilised."
Staines, a 57-year-old Baptist missionary, had worked in India since 1965 treating leprosy patients.
The judge said the Australians' work led to the conversion of some rural Indians who distanced themselves from non-Christians "and adopted the anti-customary practice of eating beef".
"Some of the non-Christian tribals in Manoharpur and nearby villages, seething at the behaviour of the tribal converts, found a messiah in Dara Singh," Pattnaik said.
A newspaper report Sunday quoting investigators said the extremists decided to kill Staines after seeing Indians eat beef, which is forbidden by Hinduism.
The judge said Singh presented himself as a "saviour of cows".
"Dara Singh with his group of men headed a crusade against Muslims trading in cattle, attacked their trucks transporting cattle, rescued and distributed cattle among the tribals and burnt trucks," the judge wrote.
Singh, whose real name is Ravindra Pal, was arrested in Orissa's forests a year after the Staines murders. He has also been accused of killing a Roman Catholic priest and a Muslim businessman in Orissa.
The death sentence must be confirmed by higher courts and Singh's lawyer has already appealed his conviction.
The Australian high commission (embassy) in New Delhi had no comment on the judge's decision to impose the death penalty. Australia does not have capital punishment.
"It is the Indian legal system that has decided to impose the maximum punishment available under Indian law," said a high commission spokesman, who added that Australia "appreciated the commitment of Indian authorities" in prosecuting the case.
The missionary's brother John Staines had argued against a death sentence, fearing it would stir up more extremism.