New Delhi, July 29 (IANS): Four persons have been arrested for murdering a father and son on Wednesday over the direction of a cooler in a roadside eatery here, police said on Saturday.

Shyam Singh Verma, 57, and his son and manager Mayank Singh, 28, were shot dead by four armed men who had come to dine at the eatery in Nangli Dairy area of Najafgarh on Wednesday night.

Deputy Commissioner of Police M.N. Tiwari identified the accused as Anil, 24, Amit Prajapati, 28, Raja Bihari, 23, and Karim Khan, 25, -- all residents of Najafgarh Delhi.

Tiwari said that Khan was arrested from Najafgarh area in the early hours of Thursday while the rest were arrested from Najafgarh on Saturday.

"Accounts of eye witnesses and mobile tower tracking led to the arrest of Karim Khan within four-five hours of the murder. His interrogation helped us in arresting the other accused," Tiwari told IANS.

On Wednesday, the accused, who were drunk, asked a waiter at the eatery to point a cooler at the eatery in their direction.

Mayank objected to this, at which one of the accused forcefully pointed the cooler towards their table and leading to a scuffle between the two.

Though Singh who was sitting at the cash box tried to rescue his son, one of the men took out a pistol and fired at Mayank and Shyam was shot later.

Shyam died on the spot while his son succumbed to injuries at a private hospital in Dwarka.

Police said that Anil had five cases registered against him, while the other three accused were school dropouts and worked as bike mechanics.