Arsalan Parwez, 21, was not driving the Jaguar whose collision with a Mercedes on Theatre Road led to the death of two Bangladeshi bystanders, police said four days after the arrest of the scion of the Arsalan biryani chain.

They said Arsalan’s elder brother Raghib Parwez, 25, was at the wheel. Raghib, who had allegedly fled to Dubai around the time his brother was being arrested, is now in police custody.

Officers said they had arrested Raghib on Wednesday afternoon in front of a Beniapukur nursing home where he had got himself admitted, allegedly to evade arrest, after returning to Calcutta on Monday. He was nabbed after he had obtained a discharge.

The recordings on the Jaguar F-PACE’s event data recorder (EDR) had led the police to Raghib, officers said.

As corroboration, they found that Raghib’s forehead and elbow showed “silicon bites” — patches of red — like those caused by the impact of airbags deployed in a crash. Arsalan had no such marks.

A doctor said the red marks are caused by an accumulation of fluid under the skin and last for three days to three weeks before they heal by themselves.

Arsalan’s family said they had handed the younger son over to the police fearing harassment by the law-keepers unless someone from the family took the blame.

“Our lawyer had misguided us. Now we have lost both our children,” Raghib’s uncle Z.A. Khan told this newspaper.

Earlier, the family had said that Arsalan’s elder brother was studying in Australia.

Raghib has been booked for culpable homicide not amounting to murder (Section II, dealing with situations where the accused has knowledge of the consequences of his act but no intention to kill), attempt to culpable homicide not amounting to murder, rash and negligent driving and mischief. Arsalan too faced these charges.

Officers said the charges against Arsalan would be amended and he would be booked for misguiding the police, stressing that his lies to save his brother amounted to causing disappearance of evidence. Some officers, though, suggested the charges against Arsalan could be dropped entirely on sympathetic grounds.

Raghib’s maternal uncle Mohammad Hamza, who had given shelter to him and helped him leave the country, has been arrested and charged with causing evidence to disappear.

Detectives at Lalbazar and the fatal squad of traffic police said they had sensed a case of “mistaken identity” after analysing the Jaguar’s EDR.

“By analysing the infotainment telematics data from the EDR, we got the phone number of the person who was last driving the car,” joint commissioner (crime) Murlidhar Sharma said. “According to this vehicle’s technology, it has to be unlocked by a mobile number that is synchronised with it. Multiple phone numbers could be synchronised with the Jaguar. We found a log of the phone numbers that had been used to drive it from time to time.”

The last phone number on the list had a WhatsApp account that carried Raghib’s photograph, officers said. Their suspicions deepened when they found that Raghib had left for Dubai on Saturday.

“We analysed footage from 45 CCTV cameras, including footage from the home of the accused, and found that Raghib and not Arsalan had left with the Jaguar that night,” Sharma said.

Arsalan’s tower location at the time of the 1.50am collision showed he was at home, an officer said.

Police sources said that although Arsalan had initially owned up to the collision, he had over the past few days been crying inconsolably and had told the police he was not driving the car. “He, however, did not name anyone.”

Officers said CCTV footage showed Raghib walking towards Kala Mandir seconds after the crash, which happened at the Loudon Street crossing, and then running towards Rawdon Street.

He had called his family after the crash and was picked up in front of a sari showroom at the Mullickbazar crossing by his maternal uncle, an officer said.

Raghib will be produced before the court on Thursday.