The officer identified only as, Milan Das, is one of the six accused in the sexual harassment of the girl sold by her mother and stepfather.
"We are looking into all aspects and are trying to identify the person alleged to be a police official by the victim," Joint Commissioner of Police (Crime) Pallab Kanti Ghosh told reporters.
The 17-year-old girl has alleged that the police official had allegedly sexually harassed her at the Phulbagan residence here of a lawyer Lovely Chadda, who had brought her from her village in North 24 Parganas district.
She has also alleged that another lawyer, Sabyasachi Roy Choudhury also sexually harassed her at Chadda's residence.
The mother of the girl, Sangeeta Mondal was arrested yesterday along with Roy Choudhury, whereas, Chadda and S Mishra were arrested yesterday in the evening.
The incident came to light after the victim ran away from Chadda's house and sought refuge with a NGO.