Police found the 7-year-old girl's body in a garbage dumpster in Kasur district near the eastern city of Lahore last week, four days after she was reported missing.
Residents of the area have said the murder was the 12th such incident in a year, and has fueled fears a serial rapist killer might be on the loose.
Two people were killed in Kasur last week when police fired at hundreds of angry protesters, who said negligence on the part of the authorities was behind the repeated killings.
The two police officers told Reuters the authorities had arrested a man who was being treated as a prime suspect, after police had questioned dozens of people in the case.
Shahbaz Sharif, the chief minister of Punjab province, where Kasur is located, visited the town on Wednesday and held a meeting with officials on the investigation.
Sharif did not confirm the arrest in his remarks to media after the meeting, but said the police and other law enforcement agencies were close to solving the case, promising a breakthrough within "days or hours".
Sharif has offered a reward of 10 million Pakistani rupees ($90,000) for anyone who provides information about the killer.
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