bump line
n.— «If still unsuccessful, the town’s fire department amasses all of their volunteers, the police department ropes off a perimeter of the surrounding area and the search volunteers form what is known as a “bump line,” said McCarron. This group assembled into the “bump line” then searches the area by grid sections while police patrol the area by squad car.» —“Missing Coventry teen found” by Nicole Wietrak Coventry Courier (Wakefield, Rhode Island) Oct. 14, 2006. (source: Double-Tongued Dictionary)