Police are searching for a man in connection to a string of armed elevator robberies at one Brownsville apartment building.Police say the robber followed people on the elevator at 390 Sutter Ave., where he held them at knifepoint and robbed them.Officials say the robberies happened three separate times, once in July and twice in August. All of the victims were unharmed.The suspect fled the scene after each incident.Police describe the culprit as a man in his 20s or 30s, about 5?9 and 160 pounds. They urge anyone with information to contact authorities.