The accused, arrested from Barwala area of Hisar district, were identified as Pramod of Kirmara village, Pradeep of Ghogharia village in Jind district, Sunil and Praveen, police said.
A cache of arms including three pistols, eleven rounds of bullets and two magazines besides two motorcycles and a mobile phone were recovered from their possession.
The accused were arrested on a tip off when they were planning to target some travellers in the area, an official spokesperson said.
During interrogation, they confessed to their involvement in the murder of a truck driver and looting of gas cylinders from the truck, he added.