BIGGEST CROOKS USE COMPUTERS, NOT GUNS : LOSSES FROM HIGH-TECH CRIMES ARE INCREASING AND PROBABLY ALREADY EXCEED THOSE FROM BANK ROBBERIES.

Byline: Denis R. Brown

ASKED why he robbed banks, the infamous bank robber Willie Sutton replied, ``because that's where the money is.'' Times have changed. As a business enterprise, bank robbery no longer offers good returns.

Indeed, it is one of the riskiest, least-rewarding criminal activities. For an average take of less than $2,000, about 80 percent of perpetrators are apprehended. Many receive stiff federal prison sentences.

The terrifying gunbattle that erupted during the botched bank holdup in North Hollywood vividly illustrated the fact that violent bank robberies in the Los Angeles area have increased recently - by 20 percent last year. But law enforcement and bank security experts agree the shootout was highly unusual.

Bank heists in Los Angeles - the bank-robbery capital of the world, according to the FBI - plummeted nearly 60 percent from their 1992 peak of 2,641 to 1,126 in 1996. Nationally, bank robberies dropped steadily from 9,388 in 1991 to 6,758 in 1995. Complete national figures are not yet available for 1996.

Most law enforcement officials and private security experts attribute the decline in bank robberies to substantial progress by banks in becoming more difficult to rob and safer for employees and customers. Security professionals call it ``hardening the target.''

Banks are installing floor-to-ceiling, bullet-resistant bandit barriers, in addition to sophisticated silent alarm systems and surveillance cameras. Banks also are introducing such devices as access-control units with airport-style metal detectors in a bullet-resistant enclosure at branch entrances. The devices can lock out anyone found to be carrying a weapon.

Also, there are fewer banks to rob. The industry trend is toward reducing the number of branches in favor of telephone banking, ATMs, offices in supermarkets and on-line services.

Given the fundamental allure of cash, of course, some small-time robbers will always try their luck at a bank. But most turn to less-protected prey such as convenience stores.

Indeed, security firms such as Pinkerton's - which has made a business of tracking bank robbers since the days of Jesse James and Butch Cassidy and the Sundance Kid - receive requests for bank guards these days.

That is the good news on bank robbery.

The bad news is that not all crooks are stupid. The more sophisticated criminals are plying their trade more effectively than ever, using computer technology. Pinkerton's is proud of its historical role in hunting down a colorful assortment of 19th century bad guys and desperadoes, but now the threat of a bank holdup is dwarfed by other security challenges facing financial institutions.

The technology we now employ to make our banks and other financial services companies more efficient and secure has become the tool of serious criminals. Electronic funds transfers have replaced bank vaults or safety boxes as the targets of these villains. And their turf has expanded worldwide. Electronic fraud is rampant in such places as Nigeria and Russia.

In one international scheme, computer hackers accessed an account and transferred funds among banks in more than half a dozen countries, from Argentina to Russia, until the money became ``lost'' in the electronic shuffle. In another instance, a Nigerian crime ring used an insider to tap a company's vendor account list and cut itself bogus checks by electronically changing the mailing address where the checks were to be sent. By the time the legitimate vendors complained, the crooks had diverted about $2.2 million.

For criminals more prone to conventional theft, the technology itself is inviting booty. Silicon chips, computer components and peripheral parts have become hot items even on the shopping lists of low-tech robbers. Postage stamp-size Pentium computer memory chips bring about $700, a value greater than their weight in cocaine or gold. They are virtually impossible to trace, and a small fortune in chips can easily be hidden in a briefcase and carried out the front door.

Losses from high-tech crimes already may far exceed those from conventional bank robberies. While total bank robbery losses nationwide totaled $59 million in 1995, the Chubb Insurance Group of Companies reports that property losses just to Silicon Valley companies ran about $1 million a week. The Technology Theft Prevention Foundation, based in Warren, N.J., reported in 1995 that the average theft of high-tech equipment reached nearly $750,000 per incident. One California company lost more than $6 million in 16 thefts in two years.

Technology firms are not the only companies at risk. Any operation with a large number of high-end computers in the office is vulnerable to thieves seeking valuable computer chips. Nor are these targets immune from violence. In 1995, gunmen struck an Irvine electronics firm and terrorized employees before leaving with an estimated $10 million in computer chips.

Yet, brainpower more than firepower likely will gain the most loot for criminals in coming years. Police and private security specialists must be prepared to outwit, not simply outgun, these computer-age criminals.