The arrested have been identified as Tofiq, Koshar Ali and Mohammad Yunus, police said.
Tofiq, a driver, worked with a Mumbai-based transport company which had asked him to deliver 320 bags of black pepper to Delhi, a senior police officer said.
When Tofiq reached Palwal area of Haryana, he along with his friends Qayum, Umarddin Kale, Md. Ansar and Rakesh unloaded the truck and loaded all the bags into another vehicle.
Later, Tofiq and his helper pretended to be unconscious and told police that some persons had robbed the bags. However, Tofiq broke down later and confessed to have committed the crime, the officer said.