The Casuarina Avenue hit-and-run case struggled for clarity on Tuesday as Noor Alam, alias Johnny, joined his friend Shahnawaz Khan, alias Shanu, in police custody after walking into Ekbalpore police station to give himself up.

Shanu and Johnny were produced in Bankshall court and remanded in police custody till January 30 despite the investigation team providing little explanation about their role in the wild run of an Audi Q7 that killed Corporal Abhimanyu Gaud of the Indian Air Force on the morning of January 13.

Prime accused Sambia Sohrab, who the police suspect was at the wheel of the Audi during the hit-and-run, was the first to "surrender" in the case.

On Tuesday, the public prosecutor didn't even mention whether Shanu and Johnnywere in the Audi Q7 that broke through police barricades to enter a restricted zone and mow down the corporal, who was instructing a Republic Day parade rehearsal.

Nobody in the police headquarters in Lalbazar could say whether Shanu and Johnny were in the Audi at the time of the hit-and-run. Officers only described the duo as accomplices of Sambia, the younger of Trinamul leader and former RJD legislator Mohammad Sohrab's two sons.

"We are sticking to that what we had said on Monday," said Debasish Boral, joint commissioner of police (crime).

Boral had said the previous day that Sambia was driving the Audi, but he wasn't the lone person in the car. He declined to disclose how many people were in the Audi apart from Sambia.

The police were specific about Sambia's role during the court hearing, saying that he was at the wheel when it breached security and hit the air force corporal at the mouth of Red Road.

Johnny apparently returned from Ranchi on Tuesday morning. A video clip shows him walking into Ekbalpore police station and someone calling him by name. He then says: " Hum Johnny. Hum ko police ne arrest nahin kiya hai. Hum Ekbalpore thane mein ja rahen hai surrender ke liye. (I am Johnny. The police haven't arrested me. I am going to Ekbalpore police station to surrender)."

The police said they were looking for the person who recorded the video.

When asked whether Johnny had surrendered, an officer said investigators had information that he had returned from Ranchi.

"Our sources in Ekbalpore spotted Johnny roaming in the area. We contacted him and he said he wanted to give himself up. He then walked into the police station," the officer said. "We had raided a place in Ranchi where Johnny had taken refuge. But he fled minutes before we reached there."

Some officers described Johnny's surrender as a "smart move".

"The police are no longer in a position to say they conducted raids and arrested him," said an officer not involved in the investigation. "There have been occasions in the past when suspects in other cases surrendered, only for the police to claim they arrested them."

The police had announced Shanu's"arrest" on Monday following a raid on the house of his uncle Mohammad Yusuf, a resident of Ajmer Sharif Gate in Delhi.

Shanu's elder brother Khalid, who had accompanied the police team to Delhi, said he went with the cops after his brother expressed his willingness to surrender.

"I was with the police team. My brother had sent word that he wanted to surrender. We are cooperating with police. Sleuths want to question my brother. Let them do it," Khalid told Metro on Tuesday at Bankshall court.

In Sambia's case, the police had said they picked him up from in front of his in-laws' house in Beckbagan. Joint commissioner Boral had said at a midnight news conference on Saturday that Sambia was arrested on the basis of "a specific tip-off".

But sources in Lalbazar said Sambia, who had fled Calcutta after the hit-and-run, returned to the city and "surrendered" somewhere on Ripon Street after consulting a lawyer.

On Tuesday, public prosecutor Abhijit Chatterjee made a short submission at Bankshall court while objecting to the bail plea moved by the lawyers representing Shanu and Johnny.

"The two accused were arrested in the past 24 hours and the police need to interrogate them separately and jointly. It is too early to say what role they had played in the incident," Chatterjee said.

Johnny's lawyer Rajdeep Majumdar accused the police of framing his client. Fazle Ahmed Khan, counsel for Shanu, said his client was in the Skoda sedan that the police had seized on Monday. He also asked the public prosecutor to explain why the car was seized.

Boral had said earlier in the day that the Skoda was "used to flee after the incident happened".