The Assam Rifles found Ram Kumar at Longwa village in the Mon district of Nagaland on Monday.
All the three apprehended arms dealers were later handed over to the Aizawl Police Station.
The aim lies to divert the youth into productive activities so as to wean them from falling prey to addictions.
The explosive was discovered two days after an AR jawan was injured while trying to defuse another bomb planted near the transit camp.
The theft was reported by Assam Rifles Unit 3 jawan Awadhesh Kumar, he said, adding an FIR was lodged on his complaint.
On October 10 unidentified persons lobbed a grenade at Assam Rifles transit camp at Purana Bazar area here.
Official sources said the attack was perpetrated near Hetlong village under Jairampur police station at around 9 am.
As nearly 40% of the Covid-19 cases in the state have been reported from the Central Armed Police Forces, there is a feeling among locals that the troops are spreading the disease.
The Assam Rifles said the guidelines issued by the MHA during the imposition of nationwide lockdown had given exemptions to defence and central armed police forces.
Two Assam Rifles jawans were injured after a hand grenade exploded at the Imphal pologround shortly after an equestrian event.
Dalai Lama had an emotional reunion with one of the seven Assam Rifles guards who escorted him to India during his escape from Tibet 58 years ago.