The federal Public Safety department says Paul Bernardo would have been transferred to a medium-security prison even if the previous version of the corrections law was still been in place.
Conservative Leader Pierre Poilievre has said the transfer would not have happened if the Liberal government hadn't changed the law.
Bernardo is serving a life sentence for the kidnapping, sexual assault and murders of teenagers Kristen French and Leslie Mahaffy in the early 1990s and has been designated a dangerous offender.
The Liberal government passed a bill in 2019 meant to end the use of solitary confinement, and amended the corrections law to say officials should ensure inmates are held in the "least restrictive environment."
A spokesperson for Public Safety Canada says Bernardo's transfer would have happened under the previous wording of that law, which was brought in by the former Conservative government of Stephen Harper
That version of the law stipulated that prisoners should be kept in prisons with the "necessary" restrictions.
This report by The Canadian Press was first published July 27, 2023.