The deceased Ravichandran and Deekshitha were residents of Otteri in the city, said police after preliminary inquiries.
Ravichandran who was employed at a factory in Otteri lost his job during lockdown due to which his wife separated from him and left for her parents house.
Ravichandran who was allegedly depressed over such developments took his daughter to Mamallapuram on Friday and checked into a hotel. Since the room remained locked till Saturday afternoon and the intercom calls went unanswered, the hotel staff alerted Mamallapuram police and opened the room door with alternative keys in the presence of police personnel.
Ravichandran was found hanging from the ceiling while Deekshitha was lying unconscious with foaming mouth. A sticker note on the TV said that Ravichandran ended his with daughter and nobody is responsible for their decision. Their bodies were sent for postmortem to Chengalpattu government hospital and Ravichandran's phone and poison bottle were retrieved from the room.
Police said that Ravichandran messaged his relative about his decision on WhatsApp. Mamallapuram police have registered a case and further investigation is on.