MINNEAPOLIS -- As U.S. Navy divers combed the gnarled wreckage of the collapsed Interstate 35W bridge yesterday, federal agents used a robot submarine, a helicopter equipped with cameras, and detailed images being captured from scanners onshore to search for the missing.
But by rush hour - five days after the late-afternoon collapse - the exhaustive and minute search still yielded no word on the fate of the eight people believed to have perished.
Seven previously hidden vehicles were found in the Mississippi River and amid the rubble yesterday, authorities said.
Officials said six of the vehicles occupants' were accounted for either as some of the five whose bodies were already identified or among the dozens who made it out alive.
But there was nothing found in a seventh vehicle known by police to have belonged to one of the missing.
"There is not easy ways to talk to the families about this stuff," said Hennepin County Sheriff Rich Stanek.
A strategy developed over the weekend has crews from a variety of agencies clearing debris and dumping it onto barges. The debris will be reassembled at a location downriver so that authorities can investigate what caused the bridge to come apart.
Authorities hope that, as the debris thins, the collapse site will yield clues to the fates of the missing. Searchers are also stationed downriver looking for bodies.
"I expect that things will start to move along pretty soon," Stanek said. "Bank to bank, our goal is to recover victims. ... There's a lot of resources being deployed here to get this mission done."
One of the resources is the Minneapolis Violent Criminal Apprehension Team - detectives whose usual work is to hunt fugitives. Instead, their skills were diverted beginning Wednesday to determining whether any of the missing survived the collapse but did not report to authorities.
With authorities initially fearing a death toll as high as 30 to 40, the unit's work was critical in helping to lower death estimates.
Detectives used emergency subpoenas for cell phone records to search for clues and updated families on each new discovery.
As divers search the wreckage and locate or identify a vehicle, the team's work also involves collating each agency's investigative information - makes and models of cars, license plate numbers, recovered items from vehicles - into a database.
"We're pulling out every tool we have," said Minneapolis police Capt. Mike Martin, who is coordinating the investigative efforts into finding the missing.
Officials are hopeful their projection of about eight people identified as missing is accurate. Still, they fear there could be more.
"There are homeless, joggers, bike riders, people from out of town whose families might not know they were missing," Martin said.
Meanwhile, federal investigators said yesterday that they are focusing on whether a construction crew working on a bridge resurfacing project could have caused vibrations that destabilized the bridge.
State transportation authorities said that two inches of concrete was taken off much of the bridge surface and then replaced.
But in eight spots, all nine inches were removed and repaired because the surface needed it there. Authorities refused to speculate whether the resurfacing of the spot repairs had anything to do with the collapse, leaving it to federal authorities to investigate.
"We're going to be looking at that entire area where the construction was being done," said Mark Rosenker, chairman of the National Transportation Safety Board.
State officials indicated yesterday that as soon as the collapse site is cleaned and combed in the coming days, it would be the focus of an intense, fast-track building of a new bridge.
As funding worked its way through Washington, officials announced that they hope to have a new bridge in place by late next year - about half the usual building timetable
Bids will be accepted tomorrow -a week to the day after the bridge collapsed.
E.A. Torriero and James Janega write for the Chicago Tribune.