How to obtain the files created by previous university researchers, both legally and physically? I'm a post doc at a U.S. University.  I need the files of a grad student research assistant who has left the lab.  The student was a funded  RA.  The student created files (data, codes, simulations, etc) for a few contracts the lab had, which funded him.  

This student has been very difficult to contact, and stubborn to send the files.  Compounding my problems, the student did his work on 2 computers: (1) his personal laptop, and (2) a lab computer which has had its hard drive wiped.  It is important to note that the student used the university internet server the entire time (it's the only way he could use university licensed software).  At this point, I have given up on him sending the files.

Questions

1) What legal maneuvers (in the US) do I have to get the files from this ex-research assistant?  I understand that he would own some of the intellectual rights of the files, but the lab and sponsor would also have some ownership.  

2) Could the files still exist within the university somehow? This RA wiped his company computer's hard drive before leaving (a relatively common practice for any exiting employee).  Since the student used the University internet server, the files could have been monitored and even obtained legally (I think).  In the US it's legal for an employer to monitor an employee if they're using company property (Internet server, computer, etc). Is it common for a major research university to obtain backup files of all the researchers' work through the Internet server?  Are the files of grad student research assistants typically obtainable within a research university (not the published dissertations but the actually files, codes, data)?  Or are the files forever gone (at least  from a practical point of view)?  I've talked to IT people but have not reached a knowledgeable person yet.  

3) If you were a researcher who left your company, would you expect (and be okay with) future employees scouring your company computer, or possibly obtaining your personal laptop files via the company Internet server (don't know if this is even possible?) ?

4). What are the ethics of this situation? What are the formalities of these situations?

Any information would help, this is really holding back the progress of the lab and my required deliverables.  The grad student left spontaneously after the semester  - otherwise the professor and lab director would have obtained the files from him.
Talk to an attorney or post your question here: https://law.stackexchange.com/
The files could still exist in a Univeristy network but you have not provided enough information to know for sure. Maybe someone here can help: https://security.stackexchange.com/ 
I would not keep sensitive personal information on a work computer and would have no grounds to compain if others later gained access to that data.
I see no ethical problem with recovering any and all files on the University netowork. Ethics regarding file recover the personal computer of the RA would depend on the ability to first obtain a court order to search it or demand the data in question is turned over in which case I see no ethical problem.