To answer your question directly, yes. I cannot give you specific time delays because I cannot exactly date the development of latents on a document processed, placed in evidence, and checked out a year or two later that has additional prints that are not in the original photographs.
But your question begs some serious concerns. What was your department doing releasing the document back to the complainant after it had been processed? I see problems for several reasons, as follow:
1. The document is, by very definition, evidence. Once you release it back to the complainant, you have destroyed any evidentiary value by giving up any chain of evidence.
2. Unless you are using a ninhydrin clearing agent, active ninhydrin remains in the paper. Therefore, any additional handling with naked skin post-processing will probably result in additional latents. Those latents, of course, are not evidence of value for the original crime, but are conclusive proof of mishandling after the evidence was collected by the police.
3. The evidence should have been sealed in a clear plastic bag after processing and photography was concluded. Sealed and taped and initialed & dated across the tape or seal. Was that not done?
4. If the document was returned to the complainant and that person or somebody else handled it without gloves, their ridge skin would probably have turned purple where it contacted the paper. In addition, it would probably have developed the distinctive rotten smell associated with ninhydrin reaction on skin. If the person has a ninhydrin alergy (rare, but not unheard of), your department could be facing a lawsuit.
The more serious question is not whether latent print development can be delayed (just accept it as fact -- delayed development CAN occur). Instead, your department should be seriously examining its policies regarding release of evidence and exposure of complainants to chemical hazards.
Just my opinon.
The views presented in this post are those of the author only. They do not necessarily represent the views of DoD or any of its components.