Assam chief minister Tarun Gogoi said on Saturday that the security at Dimapur Central Jail, from where a rape accused was dragged out and lynched by a mob, was under central security forces who failed to prevent the incident.
"The security in the jail was under central security forces who failed to stop the lynching. It is the Centre who is responsible for ensuring the security of the inmates," the chief minister said.
Riot police patrolled the city on Saturday, enforcing a round-the-clock curfew for a second day as the killing was condemned as "barbaric and inhuman".
The 35-year-old suspect, accused of raping a woman multiple times and arrested in late February, was dragged out of prison in Nagaland state by a mob before being beaten to death and strung up to a clock tower on Thursday.
"The act is barbaric, heinous and inhuman," Gogoi said of the lynching.
Gogoi said he has written to his Nagaland counterpart TR Zeliang to ensure the safety and security of Assamese people in the neighbouring state. The accused Syed Farid Khan hailed from Bosla village in Badarpur of Karimganj district of Assam. Zeliang has assured that all measures would be taken to provide security to their lives and property, the Assam CM said.
"The suspension of the deputy commissioner and superintendent of police by the Nagaland government was itself an admission of the fact that there was lapse on the part of the administration", he said.
"All possible steps are being taken to ensure safety and security of people from Assam, as well as for those from other parts of the country," Nagaland CM Zeliang said.
The mob as well as Nagaland's government earlier called the rape accused a Bangladeshi migrant. Rights group Amnesty International also condemned the killing as a "serious lapse in the criminal justice system".
"The Nagaland government must ensure that every person who was part of the mob is brought to justice," said Shemeer Babu, Amnesty India's programmes director.
Nagaland's indigenous tribal groups, especially the largest Naga tribe, have for years accused the growing population of Bengali-speaking Muslims from nearby Assam state and Bangladesh of illegally settling on their land and usurping resources.
Nagas have previously campaigned to evict Bengali-speaking immigrants from their territory, who they claim entice local girls into marriage for getting tribal status.
The Nagaland government has suspended three officials in relation with the incident.
Police have launched a search for several men who mobilised thousands of people who broke into the jail in Dimapur city on Thursday.