Police also arrested Md Russel, 18, of Gouripur upazila of Mymensingh district in connection with the murder.
Quoting local people, Md Samsuzzaman, officer-in-charge of Feni Model Police Station, said the girl went missing on Wednesday noon.
Getting no whereabouts of the girl, family members announced the missing news through loudspeaker.
Local people found the clothes of the girl near a septic tank at Mathiara Sonali Brick Field around 1 am.
Later, police recovered the body of the girl from the septic tank.
Nur Nabi, a member of Panchgachia Union Parishad, said Russel used to work at the brick field.
In primary investigation, he admitted his guilt saying he had killed the girl after rape and dumped the body at the septic tank, reports UNB.