The girl's parents, an uncle and two cousins are under investigation for murder, Lieutenant-Colonel Stefano Bove of the Carabinieri police said on Saturday (May 29).
Also read: Police race to solve record murder cases
All "are supposed to have taken part in the crime", he told reporters, while officers were combing through farmland to find the missing girl, Ms Saman Abbas.
Lt-Col Bove said the Carabinieri were inspecting "wells, irrigation canals and greenhouses".
Ms Abbas, who lived in the northern town of Novellara, last year rebelled against her family's traditional plan to have her wed to a cousin in their home country.
While still a minor, she turned to social services and last November was moved into a shelter home. She also reported her parents to the police, but on April 11 this year returned to them.
Police have been searching for her since May 5. That was when officers visited her house and found nobody, which triggered an investigation.
Officers then discovered that the girl's parents had left for Pakistan without her, and found images from a nearby security camera that made them fear the worst.
Late on April 29, five people can be seen walking away from the house holding shovels, a crowbar and a bucket, and returning after about 2½ hours.
The Carabinieri have identified the five as the family members suspected of murder. All are believed to have left Italy for Pakistan.
Meanwhile, hundreds of people took part in a solidarity rally for the missing girl organised on Friday night by the town hall of Novellara.
"Saman, tonight you are not alone and you will never again be alone," Mayor Elena Carletti said in a video posted on local news website Reggioonline.
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