Etan Patz: Search Ending With No Evidence of 6-Year-Old Boy

Etan Patz Investigation Has Disappointing End

Former ABC News Producer Lisa Cohen wrote a book on the case entitled "After Etan: The Missing Child Case That Held America Captive," which made national headlines. Cohen, who recently spoke with Etan's father again, said, "He is just so grateful that they're actually moving forward with the case. And if anything happens, it can bring some kind of peace to that family."

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Authorities investigating the case are using technological advances that can even detect whether a body was moved to reinvestigate the cold case. Vast improvements in technology since Patz disappeared, including agents that detect traces of blood and ground penetrating radar, are allowing investigators to crack "relatively old" cold cases by looking beyond what the eye can see.

Still, in a statement to ABC News, the FBI said that there is still not a significant amount of solid new evidence to report on at this time.

"It's important not to read too much into anything at this time," the statement said. "The process of removing material, sorting it and analyzing it proceeds at a deliberate pace."