I'm not sure this will help you.
When I find such cases, I look to the biographies of the suspects to see if there are any duplications of spouses, parents, or children for two (or more) profiles. I leave messages on such profiles suggesting that they be merged.
One should also pay attention to places and dates mentioned in the biographies. There will be some that will obviously not match, and these can be sorted out. It's a process of elimination, and one needs to do this extremely carefully, consulting other sources, including wikipedia for information.