When a local court granted bail to her alleged rapist Thursday, the girl lodged a protest against investigation officer Zulfiqar Ahmad at the Bet Mir Hazar police station, 40 km from Muzaffargarh town.
She then doused her clothes with petrol and set herself on fire outside the police station.
Some passers-by and policemen rushed her to Jatoi Civil Hospital from where she was shifted to a hospital in Multan as her condition became critical.
The hospital's medical superintendent said the girl had sustained 80 percent burns.
Zulfikar Ahmad and another police officer, Rai Shahid, have been suspended.
Punjab Chief Minister Muhammad Shahbaz Sharif has sought a report on the incident.
The girl had earlier approached rights activist Mukhtar Mai for help.
The girl was returning home from her college Jan 5 when the accused, along with his four accomplices, raped her in a deserted area.