Searches of a landfill and park near York on Wednesday did not produce leads about the location of Hamza Ali, who is believed dead, Upper Darby Police Chief Michael Chitwood said.
Police said they hoped someone in the York and Lancaster area would remember seeing Ummad Rushdi or his brother, Jawwad, in the days after Hamza disappeared Aug. 4.
Ummad Rushdi, the 30-year-old boyfriend of Hamza's mother, has been charged with kidnapping the boy from a home in Upper Darby. Chitwood said Ummad Rushdi has a lawyer and has stopped talking to police.
"The mom pleaded with him at least 50 times to tell her where the baby is," Chitwood said, but Ummad Rushdi has not disclosed the location.
He likened the search to finding a needle in a haystack, and announced plans to end the active canvassing on Friday unless new leads surface.
"I think beyond the defendant telling us where the baby is, we'll need a miracle," Chitwood said.
Police have said Jawwad Rushdi told them Ummad Rushdi admitted shaking the boy to death and burying him.
Chitwood said Thursday that Hamza's mother, Zainab Gaal, wanted to take the boy for hospital treatment a few days before he disappeared, because Rushdi apparently injured his arm or shoulder. The chief said Gaal was prevented from doing so by Rushdi's family.
Police suspect Rushdi may have first buried Hamza near the Susquehanna River town of Columbia, as his brother's vehicle became stuck there on Aug. 4. They think he may have then exhumed the boy's remains and given him a religious burial in another location.
Searches have been conducted in Upper Darby, in York and in Columbia, where dogs led investigators to a pillowcase that Gaal said belonged to Rushdi. They also have searched parkland and a landfill.
Police asked for information about either Ummad or Jawwad Rushdi, as well as a leased cab that Jawwad Rushdi drove. They asked people for information related in particular to the time period Aug. 4-6.
Ummad Rushdi has been jailed in Delaware County on $750,000 bail. His lawyer has not returned phone messages seeking comment.
Police have said Jawwad Rushdi has been cooperative, and he hasn't been charged with a crime. Chitwood said that police this week interviewed Hamza's father, a resident of Massachusetts, and that he is not considered to have any role in the crime.