New Delhi - The coach of India's 6-year-old marathon runner Budhia Singh was shot dead in eastern state of Orissa, police said Monday.

Biranchi Das was killed by three attackers at his training camp called the Judo Hall in the state capital of Bhubaneshwar on Sunday evening.

"Three young men called him outside and shot him at point blank range. He was gasping for breath and passed away immediately on arrival at the hospital," Bhubaneshwar police chief Amitabh Thakur told reporters.

The police ruled out any link of the murder with Budhia, whose mother earlier levelled allegations of torture against the coach.

Police officials said Das was shot dead for protecting a female model who was being stalked by local gangster.

Budhia's impoverished mother Sukanti Singh had sold him to a man for a paltry sum of 800 rupees (20 dollars) to work as a labourer. But Das claimed he rescued Budhia and adopted him into his training camp.

The duo made international headlines when the boy became the world's youngest marathon runner. Considered an athletic phenomenon, the boy entered India's Limca Book of Records when he ran a distance of 65 kilometres in a little over seven hours on May 2, 2006.

But state authorities and Budhia's mother later accused Das of exploitation, alleging that the coach was using the boy for his personal gain and abused him physically and mentally.

In August, Sukanti Singh lodged a complaint with the police. Das was arrested and later released, while the state government lodged Budhia in a state-run sports hostel. (dpa)