I met someone while traveling. We were into each other but the circumstances did not allow us to exchange numbers or addresses. We met in front of a building while he was waiting for someone and he was ringing a bell on that building. I thought it would be easier to ask the residents about him because clearly he knows one of them. Looking up his number in telephone directories is hard. I know the address of the building, so I just need to know information about the residents so I can ask one of them.