Updated

A helicopter with a camera mounted in its nose on Monday made slow sweeps as low as 30 feet above the wreckage of a freeway bridge collapse to take pictures of the debris in precise detail as divers were to resume searching for victims.

As the divers waited to head into the dark, murky water to search for the eight people missing since the disaster, an FBI team also was on the way to help.

A Mass for one of the five known victims, exercise therapist Patrick Holmes, was held Monday morning, and memorial services were planned Tuesday for marketing director Sherry Engebretsen and truck driver Paul Eickstadt.

Bridge Collapse: A Photojournalist's Perspective

It's not surprising that eight missing motorists have not yet been located, John L. Sanders, director of the Ohio-based National Underwater Rescue Recovery Institute, said Monday.

Some may have been able to escape from their vehicles but been swept downstream, he said in a telephone interview. They also could be trapped in tangles of steel reinforcing rod or pinned in vehicles by seat belts and air bags, or by debris, said Sanders, who has worked on more than 600 drownings.

Commuters found ways of getting to work in downtown without the major freeway.

"Overall, I'm pretty encouraged by this morning's commute," said Don Zenanko, a state transportation specialist who works in the metro area's Regional Transportation Management Center.

He said it appeared that most commuters left early for work on Monday, and followed the traffic updates flashed on overhead signs.

"I think we have the tools in place so that most of the motoring public can get through this without too much interruption of their daily lives," he said.

The bridge had carried up to 140,000 vehicles a day before it fell in the river Wednesday evening during rush hour.

More than 100 people were injured when vehicles tumbled into the swift current and onto broken concrete. Five people remained hospitalized in critical condition Monday morning.

National Transportation Safety Board Chairman Mark Rosenker said the city had been given permission for a contractor to begin removing the bridge remnants, a long and costly process that will begin with the staging of four cranes and then the start to the removal. Inspectors will examine the removed debris to determine exactly where and why the bridge came apart.

"It will be tough work but also sensitive work," Minneapolis mayor R.T. Rybak said Monday on CBS's "Early Show."

Sunday was a day of prayer for the dead and missing. An estimated 1,400 people filled St. Mark's Episcopal Cathedral for an interfaith service, marking what Gov. Tim Pawlenty described as the start of the healing period.

"We're here to begin the process of restoration," he said.

The Rev. Peg Chemberlin, executive director of the Minnesota Council of Churches, told the crowd that though they came in "shared anger and anguish," the city had rallied in crisis.

"It's important that we stand together and say, 'Minnesota, your heart is full of courage and compassion,"' she said. "The heroes in this moment, like the tears, are many."

Ahmed Sahal Iidle, father of Sadiya Sahal, a pregnant nursing student who was missing with her toddler daughter, was joined by about two dozen other Somali Muslims in brief prayers Sunday night at the Brian Coyle Community Center.

They prayed for the protection of the searchers and the speedy recovery of the missing. They also announced the Somali community will hold a public memorial service for all the victims Friday.

Clearing the bridge wreckage will help with the recovery operation and open a channel at least 56 feet wide to accommodate barge and boat traffic.

The NTSB said it could take as long as 18 months to complete its investigation into why Minnesota's busiest bridge collapsed. It will use high-tech software to simulate removing key support structures to see how the bridge reacts.

"If they remove a piece and it falls down the way they saw it, that's a pretty good indication they found the right piece, and there's all sorts of ways of doing that," said W. Gene Corley, senior vice president of CTL Group, an engineering firm.

Corley, who has helped investigate bridge collapses, as well as disasters such as the attacks on the World Trade Center and the Oklahoma City federal building, predicted federal officials would have a pretty good idea of the cause within a few weeks.

State officials said they hope to be able to have the bridge rebuilt by the end of 2008. Pawlenty said Sunday the cost could be as high as $350 million. The clean up is expected to cost as much as $15 million.