In May, at least 24 children had been killed when the same militant group attacked villages in Baksa and Kokrajhar districts.
According to official records, of the 45 people killed in violence in the state in May, 24 were children.
Rights activists said the killing of Basumatary, 16, once again highlighted the plight of the children living in the state's conflict areas.
The All Bodo Students' Union (ABSU), which moved the National Commission for Protection of Child Rights (NCPCR) Aug 25, has appealed to both militants and security forces not to use women and children in their armed fight.
"We seek an inquiry by the commission under the child rights protection laws to give justice to the family," the ABSU said in its memorandum to the NCPCR.
"Be it militants or our security forces, no one can use a child in their armed fight. Our children must be protected and special attention should be given to those living in conflict areas like the BTAD," ABSU president Promod Boro said.
The BTAD comprises four districts - Kokrajhar, Baksa, Udalguri and Chirang. The BTAD falls under the jurisdiction of the Bodoland Territorial Council, an autonomous administrative unit.
Three children, who became orphans in the violent attacks in Baksa district in May this year, were shifted to SOS Children's Villages, following intervention of the Assam State Commission for Protection of Child Rights.An SOS Children's Village is an international NGO working towards the welfare of the poor and needy children.
The issue of safety of children in Assam's conflict zones got much attention when a bomb blast carried out by the United Liberation Front of Asom (ULFA) in Dhemaji district had killed 10 children Aug 15, 2004.
Many children have either lost their lives or become orphans in bomb blasts or attacks by militant groups such as the ULFA, the NDFB, the Dima Halam Daogah (J) and the Karbi Peoples Liberation Army in the past decades in Assam.
Child rights activists said steps must be taken to prevent killing of children while at the same time proper counselling and assistance should be provided to those affected in the violence.
"Children are supreme assets of our nation and they are, by and large, helpless against any sort of violence," said Child Rights Coalition, an umbrella organisation of NGOs working for child rights."As a result of this helplessness, they either become direct victims of violence or get indirectly hit by the assaults and killings of their care providers which leave them vulnerable to various other forms of neglect and abuse," it said.