Four members of a family were found dead at their rented house at Sector C, Kushiabeel, on the outskirts of Dimapur town on Saturday.
Police recovered the bodies from the floor of their house at around 11 in the morning.
The dead included the parents and their two minor children.
The father was around 40 years of age while his wife was in her 30s.
Their son was aged around 13 years while the daughter was 11 years old.
Sources said the deceased worked as daily wage labourers and belonged to Muslim community from Morigaon district of Assam.
Police sources said the bodies were recovered with saliva coming out of their mouth.
A neighour of the deceased first saw the bodies and informed it to the police.
Dimapur civil hospital sources said the blood samples of the four were sent to forensic laboratory in Kolkata for examination and the report is awaited.
Sources said the deceased took cooked gourd leaves in dinner the previous night.
The exact cause of the death could not be known. Sources suspect it to be a case of food poisoning.