Quoting local UP member Miran Khan, Riazuddin Ahmed Biplab, officer-in-charge of Ghior police station, said Kajal used to go to the house of Sharif Miah, 40, to tutor his daughter.
An illicit relationship developed between them at that time.
Kajal got married to expatriate Sohel Rana one year back over phone and since then used to disturb her for continuing their illicit relationship.
On Monday night, Sharif called Kajal out to a nearby orchard and an altercation ensued between them over the issue.
At one stage, Sharif set her on fire after pouring kerosene and fled the scene.
Hearing screams, local people rushed in and took her to Munnu Medical College Hospital and then to Sadar hospital.
Later, she was shifted to Dhaka Medical College and Hospital as her condition deteriorated.
A complaint was lodged with Ghior Police Station in this connection which police turned into a case.
Police are trying to arrest Sharif and have collected some evidence from the spot.