can a bounty be returned to its owner in such a case?

All bounties are paid for up front and non-refundable under any circumstances.

So that would be: no.

Topic starter should have done more research prior to posting and prior to adding a bounty. It probably is best to let the bounty run its course and then close it. Someone might come up with a new answer independent of the duplicate that is worth a bounty.

I would VTC when the bounty reached its end. Even if there is an answer and if there are answers that differ from yours I would assume -merging- them might be the best option (that would transfer the bounty over to the other question I would assume).

can a bounty be returned to its owner in such a case?

All bounties are paid for up front and non-refundable under any circumstances.

So that would be: no.

Topic starter should have done more research prior to posting and prior to adding a bounty. It probably is best to let the bounty run its course and then close it. Someone might come up with a new answer independent of the duplicate that is worth a bounty.

I would VTC when the bounty reached its end. Even if there is an answer and if there are answers that differ from yours I would assume -merging- them might be the best option (that would transfer the bounty over to the other question I would assume).