CHENNAI: A 57-year-old man and his two sons died of suspected carbon monoxide poisoning at their home in Puzhal on Wednesday morning. Police said a mini generator was left running overnight in a closed room, which led to their deaths and have ruled out foul play.

The deceased were identified as Selvaraj (57) and his sons Sumanraj (15) nd Gokulraj (13). The boys were studying at a private school while Selvaraj ran a lorry transport business.

Police said that Selvaraj lived with his wife, daughter and two sons in Britannia Nagar near Kathirvedu.

After dinner on Tuesday night, Selvaraj went to sleep with his sons in a separate portion of the house while his wife and daughter slept in the other portion.

After they went to sleep, there was a power cut in the neighbourhood, after which Selvaraj ran the diesel-run generator in his room.

"Since there was no proper ventilation, the trio must have asphyxiated to death from the generator's smoke. There are no external injuries on their bodies," a senior police officer said.

On Wednesday morning, Selvaraj's wife knocked on the door several times, but there was no answer. After which, she peeped through the window and found them unconscious with frothing at the mouth.

Police reached the scene on information and moved them to a hospital, where they were declared 'brought dead'. Further investigations are on.