The New York Police Department searched a Manhattan basement Wednesday for at least the third time since April as part of its ongoing investigation into the 1979 disappearance of Etan Patz, the 6-year-old who vanished on his way to school.

Investigators at the site of a former bodega in Manhattan's SoHo neighborhood removed at least five large paper bags and used tools, including a shovel, from the basement.

Police dug up parts of the basement in April in an unsuccessful attempt to crack the case, and authorities said they returned to the basement last month.

Authorities won't say what they're looking for.

In May, police arrested New Jersey resident Pedro Hernandez in the boy's suspected killing.

Hernandez allegedly confessed to the murder, telling authorities that he had lured Etan to the basement of a corner store where he once worked and allegedly strangled the boy.

Hernandez has been undergoing psychiatric evaluation and was arraigned on second degree murder charges via video feed from his bed at Manhattan's Bellevue Hospital.

After Etan disappeared, investigators tried what was then a novel technique to try to find him: They put his face on thousands of milk cartons, a technique that would become more common in the next few years.

Relatives and authorities also put the images of missing children on billboards and fliers distributed by mail.

Those more assertive efforts eventually led to the AMBER alert system, which broadcasts news about missing children on TV, radio, the Internet, mobile phones and highway signs, and also puts the information on lottery tickets.