How do I complete "Find the Bitizen"?

Solution 1:

You have to wait for a mission (similar to "find the rebel spy") where someone is looking for a friend (or one of a number of other "find so-and-so" missions) and then find them. I almost gave up on that mission, but patience finally paid off.

Solution 2:

I ended up paying the 2 bux to skip this mission because I had the same problem as you - had done a few "Find the Rebel Spy" missions with no change. However, about a minute after I'd skipped it, I got a mission which said something like "So-and-so is looking for his friend! Can you find him?" and when I found them, it said, "Congratualtions, you found the bitizen!"

So from the wording, I'm wondering if maybe that would have completed the mission, if I'd waited a bit longer for it. So spy missions aren't the same as find someone missions.