The APA--Adivasi People's Army--a militant outfit had planted the bomb. Now the CRPF has arrested 16 members of the 292nd battalion of the 'terrorist outfit'.
The bomb had been planted on the track near Bhatkuchi and the explosion had caused derailment of Guwahati-Puri Express train early this month.
Police claim that it was an insurgent group active in Assam along with NDFB, Rabha Viper Army, Bodoland Royal Tigers Force and Karbi People Liberation Tigers (KPLT) among the several other militant organisations in North East that have been giving a tough time to security agencies.
Unlike groups that receive funding from Islamist networks in rest of the country, the APA and other groups active in Assam have mostly Hindu or Tribal cadre. They also have links with the Maoists in the neighbouring states of West Bengal, Jharkhand and Bihar.