Divers failed to recover any additional victims by early Friday evening as they searched through cars and debris submerged in the Mississippi River north of the site where Interstate 35-West collapsed in Minneapolis Wednesday.
Twelve vehicles have been found empty since the recovery mission began Thursday, Hennepin County Sheriff Rich Stanek said at an afternoon press conference.
The official death toll in the fatal I-35W bridge collapse remained at five, while one of the eight "missing" Stanek cited earlier Friday -- a number much lower than in previous reports -- had been accounted for. Still, Stanek cautioned against any using any concrete number for the missing, a count he said could continue to fluctuate.
The number of fatalities is still expected to climb as the dangerous recovery mission continues over the next several days.
Up to 20 dive boats were on the river upstream from the collapse site searching "targets" identified by sonar that may or may not be vehicles.
Visibility, at less than a foot, has complicated the search, as have the Mississippi River currents, which formed into "man-made eddies" because of the debris. Officials at the Army Corps of Engineers have been adjusting the river's water flow to try to control dive conditions, but the process has been slow because of the need to ensure the safety of the rescue workers.
Authorities also identified Minnesota resident Paul Eickstadt, 51, as the fifth confirmed fatality Friday.
Thursday evening, officials identified four Minnesota residents confirmed dead in the bridge collapse: Sherry Engebretsen, 60; Julia Blackhawk, 32; Patrick Holmes, 36; and Artemio Trinidad-Mena, 29.
Mark Rosenker, the director of the National Transportation Safety Board, said Friday afternoon that four videos provided by the Army Corps had given investigators early clues about the collapse.
"We noticed that this (southern) section of this part of the bridge seemed to behave differently in the video and in the final way it sat after the collapse," Rosenker said. "It appears it has shifted 50 feet to the east."
Rosenker said he didn't want to give the impression that investigators had the answer to the collapse, but he also called the discovery a "step forward."
"We haven't ruled anything out, anything except we believe this is an accident," he said.
President Bush is expected to visit the site of the collapse Saturday, while first lady Laura Bush toured the scene Friday.
The 500-foot span, part of I-35W, gave way shortly after 7 p.m. EDT Wednesday as slow-moving traffic crawled along the steel arch truss bridge. Some vehicles fell more than 60 feet into the river, while others ended up in awkward positions, battered by concrete and tangled in steel that exploded in all directions when the span gave way.
Federal officials alerted states Thursday night to immediately inspect all steel deck truss bridges within their borders — a total of more than 750 bridges across the country.
Officials in several states had previously said that they planned to reinspect their bridges in light of the collapse, and in Minnesota they had already began inspecting their bridges.
In 2005, the federal government rated the Minnesota bridge as "structurally deficient," a status that does not require that a bridge be closed or replaced.