In a big breakthrough in the Tirong Aboh assassination case, the National Investigation Agency (NIA) has arrested an NSCN-IM cadre in connection with the killing of Arunachal Pradesh NPP MLA Tirong Aboh and 10 others on May 21.

Besides the arrest of the NSCN-IM cadre from Dimapur, the NIA is also questioning several others in connection with the incident.

The NIA has arrested accused Yangte Josaham who is the area commander of Longding district in Arunachal Pradesh in addition to two others, Senthok Kangnong and Napong Jenpi.

This is the first major breakthrough into the gruesome killings that shook the region just ahead of the results of Lok Sabha elections and state assembly polls in Arunachal.

Earlier, last week the NIA had released pictures of five militants suspected to be involved in the killing.

42-year-old Khonsa West MLA Tirong Aboh was shot dead along with his son, family members and others near Bogapani in Arunachal Pradesh while they were returning from Dibrugarh in Eastern Assam.