Additional District and Sessions Judge Udit Chowdhury yesterday awarded the sentence to police inspector Dilip Guha for raping the girl.
The court further ordered three-year imprisonment for Chowdhury's domestic help Minati Das, holding her guilty of abetting the crime.
Minati had handed over the girl to Dilip in October, 2010, who subsequently raped her.
The victim's father later lodged a complaint to Kalyanpur police station in the district.
