In this case, it is unclear who owns the copyright and a court would probably have to be involved to clarify the situation.
While it's strictly true that we haven't been told enough to know, I would expect even the most fair and reasonable of employment contracts to transfer the copyright to the employer by default if we're talking about a project that is in exactly the field that the employee works in at their job.
While it's strictly true that we haven't been told enough to know, I would expect even the most fair and reasonable of employment contracts to transfer the copyright to the employer by default if we're talking about a project that is in exactly the field that the employee works in at their job.