Key Accused in 2021 Assam Rifles Convoy Ambush Arrested in Manipur
A joint team of Assam Rifles and Manipur Police has arrested Thiyam Boycha Singh, also known as Balin or SS Capt Balin, a key accused in the November 13, 2021 ambush in Manipur that killed Colonel Viplav Tripathi, then Commanding Officer of 46 Assam Rifles, along with his wife, their young son and four other personnel. The arrest, made on Saturday night, August 22, in Thoubal district, comes nearly five years after one of the most shocking attacks on security forces in the state.
Officials said the 28-year-old self-styled captain of the banned People’s Liberation Army (PLA) was apprehended from Lilong Ushoipokpi in a targeted, intelligence-led operation. The action was carried out under the aegis of the Eastern Command by an Assam Rifles formation under Spear Corps, working in close coordination with Manipur Police.
According to the security agencies, precise inputs generated by Assam Rifles pointed to the militant’s presence in the area. Some reports said the trail initially led to Bishnupur district before the interception was made in Thoubal. On-the-spot questioning confirmed his identity, after which he was handed over to Lilong Police Station for further legal proceedings.
Police said Balin was carrying a National Investigation Agency-declared reward of ₹4 lakh and had been listed as the third accused, or A-3, in the NIA case linked to the ambush. He had also been declared an absconder. Security officials said preliminary interrogation suggested that he was part of the team that carried out the attack on the 46 Assam Rifles convoy at Behiang in Churachandpur on November 13, 2021.
Further questioning, officials said, indicated deeper involvement in PLA activity. This included training, a prolonged stay at a militant camp in Myanmar, procurement and transfer of war-like stores, and maintaining links with other insurgent groups.
In a post on X, the Army’s Eastern Command described him as “a key accused in the 2021 #Churachandpur ambush case of Colonel Viplav Tripathi, his family members and security forces.” It added that the operation “reaffirms the resolve of security forces to disrupt insurgent networks and safeguard peace and stability in #Manipur.”
The arrest was part of a wider wave of coordinated counter-insurgency operations carried out over the previous 24 hours in Thoubal, Kakching, Tengnoupal, Imphal East and Imphal West districts. In those operations, Manipur Police, Assam Rifles and other Central forces apprehended eight militants belonging to banned outfits including the PLA/Revolutionary People’s Front, PREPAK, KYKL and the KCP. Security forces also recovered arms, ammunition, incriminating documents, subscription receipts, cash, seals and letterheads of banned groups.
How the 2021 ambush unfolded
The attack that led to the present arrest took place on the morning of November 13, 2021, when a convoy of 46 Assam Rifles was ambushed near S Sehken, also referred to as Sehkan or Sialsih, village under Behiang police station in Churachandpur district. The site lies close to the India-Myanmar border along the Tedim Road.
Colonel Tripathi was returning from the Behiang company post to the battalion headquarters when the convoy came under fire. He was travelling with his wife, Anuja Tripathi, and their young son, whose age was reported in contemporary accounts as between six and eight years old. Some reports identified the child as Abeer. The convoy included multiple vehicles, among them a black Bolero carrying the officer and his family.
Investigators later said the militants first triggered an improvised explosive device that struck the pilot Gypsy, forcing the convoy to stop on a narrow stretch of road about 10 feet wide and curving through thick trees. The spot was later described by those who visited it as a “textbook-perfect” ambush location. Heavy automatic fire followed.
Seven people were killed in the attack: Colonel Viplav Tripathi, his wife, their son, and four Assam Rifles personnel — Rifleman Suman Swargiary, Rifleman Khatnei Konyak, Rifleman R.P. Meena and Rifleman Shyamal Das. Several others, including personnel from the Quick Reaction Team, were injured and evacuated in difficult weather conditions.
The People’s Liberation Army of Manipur and the Manipur Naga People’s Front jointly claimed responsibility for the ambush. In their statement, they said their cadres were unaware that the Commanding Officer’s family was travelling with the convoy and criticised the presence of families in a disturbed area.
The National Investigation Agency later took over the case and registered it under sections of the Indian Penal Code, the Unlawful Activities (Prevention) Act, the Arms Act and the Explosive Substances Act. In January 2022, the agency announced cash rewards ranging from ₹4 lakh to ₹8 lakh on ten accused members of the PLA and MNPF linked to the attack. Balin was among those named, with a reward of ₹4 lakh.
Over the years, investigators have arrested several accused in connection with the case. These include Sagolshem Sanatomba Singh, described as an active PLA cadre and one of the prime accused on the NIA’s wanted list, who was arrested in May 2025 from Thoubal district. Earlier, MNPF cadres such as Machukring Zamshim Shimray and Solomon Jamir were also taken into custody. The latest arrest of Balin is another step in efforts to trace those still at large in the case.
The 2021 ambush remains one of the most distressing incidents for Assam Rifles and the broader security establishment in the Northeast. It was not only the killing of a serving commanding officer that shocked the force, but also the death of his wife and child. The attack also highlighted the continuing threat posed by valley-based insurgent groups with cross-border linkages in Myanmar, even as Manipur has continued to face fluctuating levels of violence amid ethnic tensions and other security challenges since 2023.
Security forces have maintained pressure on PLA, PREPAK, KYKL and other outfits involved in recruitment, extortion, arms procurement and attacks. Officials said the latest operation again showed the value of coordinated, intelligence-driven action by Assam Rifles and Manipur Police in a complex security environment.
Investigators are expected to question Balin further for leads on remaining absconders and on the wider network behind the 2021 ambush as well as current PLA activity. His alleged role in training, logistics and links with other groups in Myanmar is also likely to remain a key part of the probe.
