Superintendent of Police Rakesh Kumar said police have also arrested five persons and seized Rs 4.95 lakh, three country made pistols, six cartridges, three motorcycle and four mobile phones from their possession.
All the miscreants were arrested from near Sultapur village of Industrial police station area.
One of the five arrested persons is the son of a postal employee, the SP said.
The five men had also injured two homeguards trying to snatch arms from them on November 21 last when they looted the money from a cash van at post office premises.
All the cash that have been recovered are old currency notes of high denominations, he said.
The cash van the accused looted was collecting cash from different post offices of the district for depositing them with the Head Post Office at Hajipur, District Postal Superintendent U C Prasad said.