The police have found three suicide notes from the house near Parlakhemundi Royal Palace.
The suicide of four siblings who worked for a former king and lived near his palace in Odisha's Paralakhemundi town has sent shock waves across the state and has forced the government to order a full investigation.
The bodies of former palace manager Ananga Manjari Patra, her brother Sanjay and sister Bijaylaxmi were found inside their house near the palace on Sunday after neighbours complained of a stench.
Last night, another brother Santosh died before he could record his statement with the police. He was found in a critical condition in the kitchen of the house the siblings - six in all - shared.
The police suspect a suicide pact after Ananga Manjari Patra was accused by an organization of trying to grab royal property and holding ex-king Gopinath Gajapati Narayan Deo captive.
Sanjay allegedly hung himself while the others took pesticide.
The Maharaja, as he is locally called in this town around 280 km from state capital Bhubaneswar, is 74, and in a hospital in Chennai.
All the siblings were unmarried.
Ananga Manjari was the estate manager and confidante of the former royal, who is believed to own a fortune worth Rs 500 crore.
A "Maharaja Suraksha Committee" - a forum of citizens that took on the job of "safeguarding" the royal wealth - alleged a swindle by the siblings and went to the police against them on August 14.
The police have found three suicide notes from the house, which was bolted from inside.