The sentries, who were guarding the Bihar Military Police (BMP) armoury at Muzaffarpur when five assault rifles were stolen, will be subjected to a lie-detector test, a top Bihar police official said on Tuesday.
The official, speaking on condition of anonymity, said 20 sentries were posted at the armoury when the theft was detected on August 27.
"All these sentries will be subjected to a lie-detector test and if we find any suspicious behaviour during the interrogation of others, they too will have to undergo the test," he said.
The official said since a lie-detector machine was not available in Bihar, the Muzaffarpur district police had sought it from Delhi.
The machine will be installed at the CBI office in Patna, where officials of the investigating agency will question the sentries, the officials said. If the machine cannot be brought to Patna for some reason, the sentries will be sent to Delhi to undergo the test.
The disappearance of four AK-47 rifles and an Insas rifle was detected on Sunday, when the armoury was opened for a routine weekly cleaning of weapons of the BMP 6th battalion.
A case was registered with the police in Muzaffarpur the same day.
Earlier, an AK-47 assault rifle and and 60 bullets had gone missing from a CRPF camp in Muzaffarpur on August 24.