Susan and Christopher Edwards will remain in custody until their appearance before Nottingham magistrates tomorrow, police said.
The pair, of no fixed address, have been charged with murder after the remains of a man and woman were found buried in the back garden of a house in Mansfield on 9 October.
Following a post-mortem examination, a Home Office pathologist determined both died as a result of being shot.
Formal identification has yet to be confirmed, but detectives believe the remains are that of William and Patricia Wycherley who lived at the house in the 1990s.
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Scientists used modern forensic techniques to review the 'cold case' and determine the victim was probably killed by two blows to the head.