The man also suffered burns in the attack that sent shock waves across the state.
The man who allegedly burnt a woman tahsildar alive in her office near Hyderabad over land dispute, died at a hospital in the city on Thursday, police said.
On November 4, Tahsildar Vijaya Reddy died after she was allegedly set on fire by K Suresh.
"Suresh succumbed to his injuries at around 3.25 PM on Thursday at the hospital while undergoing treatment," a senior police official told PTI.
The assailant walked into the Tahsildar's chamber and poured petrol on her before setting her on fire using a lighter.
He also suffered burns in the daring attack that sent shock waves across the state.
Police said a scientific investigation was underway and they were probing from all angles to ascertain the exact reason that provoked K Suresh to set the Tahsildar on fire.
They also said they are holding inquiry with K Suresh's family members and verifying the land documents as part of the probe.
K Suresh had told police he was a farmer and into real estate business.
He co-owned a 7-acre agricultural land with his brother, which was transferred to a tenant and a disputehad arisen over it and a litigation was in the high court.
However, his family had claimed that he would not have resorted to the act alone and was provoked by some others.
The driver of the tahsildar who sufferred burns in a bid to stop the assailant from setting her on fire, had died at a hospital in Hyderabad on November 5.
The shocking incident triggered protests by Revenue department employees across Telangana, while political leaders condemned it.