A robbery in Nebraska that left five people dead last month is part of a disturbing national trend that has seen a sharp rise in the number of rural bank stickups.

Between 1995 and 2000 -- the most recent years for which FBI statistics are available -- small-town bank robberies rose 49 percent, compared to an overall national rise of just 6.7 percent. The only decline was in suburban bank robberies, which fell 32 percent.

And officials can't explain the trend.

Finding reasons for the spike is a "purely speculative" exercise, according to FBI spokesman John Iannarelli. He said one factor could be a perception that small-town banks make easier targets.

"You'll find crime wherever there's the opportunity or the perception that there's opportunity," he said.

The killings and botched Sept. 26 heist of the U.S. Bank in Norfolk, Neb., shocked the normally quiet community, and has led leading analysts, law enforcement officials and the media to take a closer look at bank robbery trends across the nation.

"It's the kind of thing that alarms everybody," said David James, police chief of Carrollton, Texas, a Dallas suburb.

James said he has noticed a slight increase in bank robberies in his and surrounding towns in recent years. The trend often runs in cycles, with gangs of robbers hitting a series of banks in one area until they're caught.

James attributed the rise in part to the increase in grocery store bank branches and the absence of armed security guards, who were once ubiquitous at nearly every bank door.

"If conditions have changed, it becomes more attractive," James said. "(Bank robbers) tend to be fairly bold."

Others speculated the shaky stock and job markets are fueling the upward swing.

"When jobs are plentiful, a lot of people don't have to commit crimes," said Raymond Simmons, police chief in Humboldt, Tenn. "If they lose that, they're going back to another way of making money."

Simmons said there has been a slight increase in bank holdups in Humboldt over the last seven years.

"Probably professional criminals try to scope smaller town banks -- they try to find the most vulnerable target," he said. "The perception is that a small town could be an easier hit."

But that isn't necessarily true.

"It's a false perception," said Chief James. "Banks in rural areas have the same protection as banks in cities."

Since most banks are federally-insured facilities, the FBI has jurisdiction over bank robberies. Agents work with local officials to nab the thieves -- meaning at least two law enforcement agencies tackle each case.

"The solution (crime-solving) rate for bank robberies is pretty great," Iannarelli said, pointing to Nebraska, where all four suspects were snagged within hours of the Norfolk heist.

Simmons and other police chiefs say officers have become more active in patrolling neighborhood banks -- with random, unannounced checks; frequent communication with tellers; drive-by surveillance of suspicious activity; and even decoy police cars parked at banks with their motors running.

"We have a very aggressive patrol procedure on our banks here," said J.D. Sanders, public safety director at the Martin, Tenn., police department --which hasn't seen a bank robbery in 20 years. "There's a strong presence in and around banks."

Others wonder if the FBI, which has focused its efforts on the war on terror, has the proper resources to chase down bank robbers. But for now, at least, the bureau is confident it will manage.

"While terrorism has become our No. 1 priority, bank robberies are still something the FBI works on an active basis," Iannarelli said. "We have to investigate. We're held accountable."