Buying with Listing agent or Buyer agent for off-market property?

[Tony Zhang]

I'm interested in a duplex and submitted my offer with my buyer agent. I call the listing agent and she told me that seller has accepted other offer that is above asking price. But, she said there's also an off-market duplex available for sale in this community with the same asking price. At this time, I don't want to miss this opportunity should I make offer directly with this listing agent to get highest chance of accepting offer or talk to my own buyer agent (which she doesn't know this off-market deal, and I don't want she to spread the word to other interest buyer and increase my competition) and see if she can help me with submitting offer? 

Who should I choose and what's the pro and con between listing agent and buyer agent for an off-market deal?

Any comment on this is appreciate!