The accused had looted Rs 8,50,000 in cash on October 28 last year from the firm manager.
Amethi Superintendent of Police Hira Lal said the arrested were identified as Arvind Pratap Singh, Suraj Singh, Roshan Upadhyay and Durga Prasad. While the first three were residents of Amethi district, the fourth hailed from Rewa in Madhya Pradesh.
A car used in the commission of the crime, Rs 1,93,000 in cash, some weapons and mobile phones were recovered from the accused, the SP added, adding the police team which nabbed the culprits would be given a cash prize of Rs 5,000.