Seeking location of executed Civil War soldiers' graves

Seeking location of graves of executed Civil War soldiers. Trying to find anonymous graves from two double executions in Virginia (Union deserters), likely buried with shackles still on, in Nov 1863 and Jan 1865. Would those remains have been collected/sent to National Cemetery?

Two double executions in Virginia: Nov 1863 "near Bowers Hill" (close to Portsmouth VA); and Jan 1865 "outside the lines near New Market Rd" (between Petersburg and Richmond VA).  The first of these was recorded in news accounts as prisoners shot as they stood next to their coffins.  They were buried near where they fell.  The other place name was Ft Reno, near Bowers Hill, but I think that name for the fort was only used for a short time - haven't found any record using that name otherwise.

The second execution would have been in the Bermuda Hundred vicinity; the regiment/brigade had fought at Chapin's Farm and Ft Harrison in Sept 1864.  I have found no detailed news account of this execution - only a few words announcing that it occurred.  The Court Martial record provides no specific location.

None of the 4 names is found in any searchable record for national cemeteries.  The anonymous burial would have been part of the dishonor bestowed on the deserters.  Assuming the graves were found in the general search for soldiers' graves, would any record have been made if the remains were shackled?  Would they have just been included as unknowns?  Is there any way to find out where the bodies ended up?