The FOIA request was for all the data on Seth Rich’s laptop. The FBI now claims that they never actually downloaded the data from Rich’s laptop, but it was given to them by a police department.
I imagine the data could possibly show that Seth Rich was the source of the leaked DNC files. If that were the case, then it would turn his murder investigation into something more than just a botched robbery gone bad.
Seeing how the FBI seems to be biased towards Democrats, it’s no wonder they want to hide the data.