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In this paper we analyze upward connecting leaders induced by some downward negative lightning flashes that struck an ordinary residential building located in São Paulo City, Brazil. Most of what is known about the current of downward flashes comes from information gathered on towers. There are no observational data of lightning attachment to common structures or buildings (under 60 m) that are present in almost every city. For the first time, the attachment process was analyzed by a high-speed camera running at 10,000 images per second. The striking distance observed was larger for return strokes with higher peak currents. The ratios of speeds of the downward leader and the upward connecting leader varied from 1 to 9. The final jump discharge initiated from the positive upward connecting leader.