Patna: Kundan Prasad, the father of the youth from Patna shot dead in a bus in suburban Mumbai on Monday, claimed his son did not have any criminal antecedents and sought a high-level inquiry into his killing.

A shaken Prasad, who runs a garage here, said his son, an x-ray technician, had gone to Mumbai last Friday in search of greener pastures.

Patna Senior Superintendent of Police Amit Kumar, who along with District Magistrate Jitendra Kumar Sinha, visited Rahuls home, claimed the youth did not have a criminal background.

"We have been told by his neighbours that he was a regular sort of person belonging to a respectable family," Kumar said.

"We went to verify the kind of a person Rahul was and whether he had any criminal background, particularly since the incident has occurred in the aftermath of a string of violent incidents targeting Biharis in Maharashtra and retaliatory protests in Bihar," he said, adding the investigation would be done by the Mumbai police.

While speaking to the media in Delhi, Bihar Chief Minister Nitish Kumar said though a detailed inquiry would reveal the truth, the television footage suggested the youth could have been captured instead of being shot.

Kumar is in Delhi to meet Prime Minister Manmohan Singh to seek stringent action against Raj Thackeray.

Bihars Director General of Police D N Gautam said the chief minister has instructed him to send a top police officer to Mumbai for a preliminary inquiry.

IG (CID) Rajesh Ranjan would go to Mumbai to go into the circumstances leading to the killing in the encounter, Gautam said.

The railway authorities have been put on a high alert following the killing which came close on the heels of violent protests across Bihar after attacks on railway job aspirants from the state by Thackerays Maharashtra Navnirman Sena (MNS).

"Reinforcements have been rushed to all railway stations in Patna Railway district particularly after mobs protesting against attacks on Biharis in Mumbai targeted railway property," Superintendent of Railway Police D N Gupta said.

Local BJP MLA Arun Kumar Sinha, who visited the family to console them, said "it is surprising how a person who never killed a bird, shot at the police." He demanded a CBI inquiry into the incident.

23-Year-old Rahul Raj was shot in retaliatory fire by police in Mumbai suburb of Kurla after he opened fire.