Police arrested Prakash Rajkonwar alias Chao Naam Ti Lao, 65, from Milan Nagar, Dibrugarh, on suspicion of his involvement in the May 15 Guwahati blast.
Eleven persons, including two SSB jawans, were injured in the grenade blast in Guwahati on May 15.
The Ulfa (Independent) has claimed responsibility for the blast.
According to eyewitnesses, the grenade was lobbed from a motorbike. Others said said it was hurled from within a moving SUV at a temporary security checkpoint manned by Assam police and SSB from opposite the façade of a shopping mall in the densely populated and busy commercial area on Zoo Road.
Prakash was arrested from the rented house of Sundar Rajkonwar. The police have seized a computer and four mobile handsets from him.
He is retired teacher of Dirak LP School.
A team of Guwahati police arrived in Dibrugarh on Sunday after getting information about Prakash’s involvement and arrested him from the rented house.
Both Dibrugarh and Guwahati police interrogated him at Dibrugarh police station. He was taken to Guwahati for further investigation and he will be produced in court on Monday.
Although the police refused to share details, they revealed that Rajkonwar kept close contact with the Guwahati blast accused and used to stay with them during his visit there.
The police have so far arrested pro-talks Ulfa leader Pranamoy Rajguru, Assamese actress Jahnabi Saikia, former president of the Gauhati University Post Graduate Students’ Union Sanjib Talukdar, Chinmoy Lahkar, Amit Ballav Goswami and Indra Mohan Bora.
The prime accused senior Ulfa-I leader Bijoy Asom was arrested from Tinsukia on May 21.