Three of the four accused have been arrested since.

Kumar, who is 65 per cent hearing impaired, said the foursome had probably trailed him into the bus (on route-number 8; Noida to Badarpur). He was in Noida to pay the fees for his MBA course at Amity University. They were eyeing the hearing aid that he had removed and put in his pocket after getting on the bus, Kumar said.

Within minutes, as the bus neared Sarita Vihar crossing, one of them reached into Kumar’s pocket and removed the machine. “I asked them to return it; I told them it would not work if a single wire gets loose or removed,” Kumar said. They could not have done anything with the machine, though it costs Rs 1 lakh — “but they did not listen to me.”

The four got off the bus at the traffic signal near NTPC; Kumar followed suit, still urging them to return the hearing aid. “I could not hear clearly but they were shouting — I could make out vaguely that one of them said, ‘Chikne, kill him’.”Then came the blows. With a rod. “They hit me on the head repeatedly and then took out Rs 10,000 that my father had me given for admission.”

But the ordeal was still not over — Kumar said the assailants then took him under a flyover and beat him up further. “I lost consciousness at this point and they fled. But no one came to my aid,” Kumar said.

A PCR van later took him to AIIMS. Kumar was in the trauma centre for two days and promptly registered a case once released.

Based on Kumar’s description, the police arrested three of the goons on Saturday. The arrested persons have been identified as Moni (17), Suraj (17), and Suraj Lal (18).

The police said the fourth, “gang leader” Kamal Chikna, is absconding; the money they took they took from Kumar has also not been recovered yet. The police said Chikna has several cases of pick-pocketing against him.