Nishant Arora, 29, and Gaurav Sharma, 27, were attacked by the accused on the night of September 16 and 17 after the duo intervened in an argument among the four over giving way to one of their vehicles.
Of the four, three were on a motorcycle, and the fourth was driving a car.
According to the FIR, Mr Arora and Mr Sharma were heading towards Jheel Chowk in Geeta Colony on a scooter when they found three motorcyclists arguing with the car driver.
Mr Arora and Mr Sharma tried to pacify them. But one of the motorcyclists stabbed the duo, the police said.
Mr Arora was declared brought dead at a hospital and Mr Sharma was being treated at the GTB Hospital, they added.
They were arrested from Haridwar late last night, said Nupur Prasad, Deputy Commissioner of Police (Shahdara).
The police suspect the four accused were drunk during the argument.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)
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