Bank robberies in Lake and Porter counties jumped three-fold in 2007 from the year before, bucking state and national trends, federal statistics show.

Lake County banks were robbed 23 times in 2007, compared with eight such incidents in 2006. In Porter County, three bank robberies were reported last year after the county went all of 2006 without a single incident, FBI records show.

Already in 2008, robbers have hit four banks in Lake County and one in Porter.

Meanwhile, FBI statistics show bank robberies across the nation hit a 10-year low in 2007, down 23 percent from the year before. Bank heists in Indiana were down 15 percent last year.

All but four of the robberies in Lake County involved a weapon -- an act authorities say substantially increases criminal penalties for those who are caught.

Reports of the increase in robberies come as authorities investigate serial robbers, including the "Kangol Bandit," who is thought to be responsible for heists in Hammond, Highland, East Chicago and Calumet City.

Edward Eason, 57, of Chicago, faces charges in connection with two of the 11 robberies that the FBI considers to be the work of the "Kangol Bandit," so named for the suspect's choice of distinctive designer hats. He is a suspect in at least six other robberies during the past four months, authorities said.

Police also are investigating whether the three robberies in Porter County -- all at First National Bank in Valparaiso -- are related.

Paul Freeman, executive vice president of the Indiana Bankers Association in Indianapolis, said a downturn in the local economy is a likely factor driving the increase in region bank robberies.

"I'm no sociologist, but I would say most crime is an act of need or perceived need," he said.

Freeman said the banking industry has dedicated large sums of money and time in recent years to training its employees on how to handle robberies and on technology to fight the crimes.

While he declined to name every tactic banks use to deter robberies, he said institutions typically have blanket surveillance and use silent alarms, exploding dye packs and recorded serial numbers to help catch robbers.

FBI spokeswoman Wendy Osborne had two pieces of advice for customers and employees who witness bank heists. First, do whatever the robber says.

"We certainly would want customers and employees to be cautious and cooperative," Osborne said. "We wouldn't want someone to get hurt. It's not worth it."

And then afterward, bank tellers need to be the best witnesses that they can, making note of suspects' weights and heights, she said.