A young man walked into the Riggs National Bank office at 1875 Connecticut Ave. NW a week ago Friday, shoved a note at the frightened teller and strolled out the door with a bundle of the bank's money.

The same day the same men did the same thing at the First American Bank branch at 1325 G St. NW, using neither a weapon nor a disguise to rob the bank.

District police now are circulating surveillance camera photographs of the man who committed bank robberies number 50 and 51 and put the District on its way to a record year for bank holdups.

Bank robberies are running 50 percent ahead of last year in Washington.

Maryland is even worse, with 106 robberies so far, twice as many as were committed in the first six months of 1980. Suburban Virginia had 40 robberies last year and already has had 31 this year.

The result is what the FBI says is the worst year for bank robbery in the nation's history.

Robbery of financial institutions -- banks, savings and loan associations and credit unions -- now is the fastest-growing crime against business in the Washington area and much of the country.

Robberies have become such a routine part of the banking business that learning how to be held up is now standard training for tellers.

Banks have been forced to remodel their branches, change their operating procedures, stiffen their security systems and prepare as inconspicuously as possible for the robbers to come through the door.

The money stolen is not the problem, bank officials say. The average bank robber gets away with less than $2,000 and the $45 million stolen in all U.S. bank holdups during fiscal year 1980 was a fraction of what the banks lost to embezzlers and other white-collar crooks.

But a robbery can shatter the morale of tellers, and turn off customers who see banks as a vault of security.

Because they fear upsetting employes or customers, most bankers are reluctant to talk about the disturbing increase in crime.

The bankers' reticence may be contributing to the crime wave, some lawmen believe. They say the banks could deter robbers if they were willing significantly to improve the security of their branches.

Bankers are afraid that caging tellers behind ceiling-high panels of bulletproof glass, installing more conspicuous anticrime cameras, or hiring armed security guards might scare off customers as well as crooks.

Whether anything the banks or anyone else does will discourage crimes against financial institutions is an open question.

Banks keep getting robbed, despite the fact that most robbers are caught and the overwhelming majority of them wind up in federal prison.

"Bank robbery looks easy until you look as the solution rate. "It's not easy to get away with," said W. Thomas Moore, head of the bank robbery squad for the Maryland FBI field office.

About 70 percent of the Maryland and Virginia bank robberies last year were solved and the catch-rate in the District was 90 percent.

Part of the reason the District is more successful is that it has its own highly regarded bank robbery detail. Another part of the reason is that urban bank robbers are different from suburban holdup men, explained Sgt. Edward Dory, head of the District's bank squad.

Most District banks robberies are "not jobs." The lone robber (usually a young man) slips a teller a note, grabs whatever he is given, walks out the door and tries to disappear into the city. Like the man who pulled the last two District robberies, most of them don't use guns or even wear a mask.

Suburban bank robbers more often are "counter jumpers." Usually there is more than one of them, they tote guns and typically drive a stolen car. The surburban modus operandi is to jump behind the counter, get the drop on the staff, scoop up the cash and make a high-speed getaway.

"The suburban types are the problem," said Theodore Gardner, special agent in charge of the Washington field office of the FBI.

The local FBI office gives a high priority to what Gardner called "the violent-type crimes with multiple perpetrators."

The guns and the getaway from a suburban bank holdup can lead to dangerous chases and even shootouts, making the suburban robberies a far more serious threat to bank employes, customers and law officers.

Holding up any bank, savings and loan association or credit union is a federal crime, and local FBI agents scramble everytime a bank robbery goes down.

When the crime occurs in the Washington area, a "flash alert" immediately is sent to FBI field offices in the District, Maryland and Virginia and all local law enforcement agencies, under a system set up last fall shortly after Gardner was assigned to run the Washington office.

Robbers frequently knock over a suburban bank, then flee into the District or across the Potomac, in the hope that police will not be looking for them there, the local FBI chief explained.

Gardner said he now is considering another antirobbery tactic that has been used successfully in Minneapolis, where he formerly headed the FBI office, and in Detroit, one of the worst bank robbery targets in the country.

In those cities, selected local radio stations break into their regular programs to broadcast descriptions of robbers and getaway vehicles immediately after a bank is hit.

The idea is not to encourage civilian volunteers to tackle armed robbers, but to mobilize public eyes to try to spot crooks as quickly as possible.

The best time to catch a bank robber, authorities explain, is right after the holdup.

Those who elude the immediate dragnet usually find their pictures plastered all over local police stations, thanks to the cameras that now are standard equipment in most banks.

The ubiquitous anticrime cameras are the most important weapon police have developed in the fight against bank robbers. Even the best descriptions or sketches can't match a photograph of a criminal in action as evidence or an aid to investigations.

But some banks are so poorly lighted the pictures are barely usable, complains Baltimore FBI agent Moore; others don't bother to keep fresh film in their cameras or are sloppy about other anticrime measures.

"Banks need to enhance the security of their individual branches," he said. "I feel that we are getting the message through to the major banks that are able to have a professional security officer, but when you get to the smaller banks, the security officers have four or five other duties to perform."

Moore's boss, Edward Hegarty, special agent in charge of Maryland and Delaware, said the consumer marketing push that leads banks to open more and more branches is one of the reasons why bank robbery is growing.

"Part of the problem is branch banking," Hegarty said. "The more branches there are, the easier it is to rob a bank." It is not the big banks in downtown Baltimore that Maryland robbers hit, he noted. It is the little ones scattered around the Washington and Baltimore beltways.

One band of bank robbers became known as "beltway bandits" after specializing in branches convenient to beltway exits.

Repeaters are common among bank robbers, many of whom practice their trade until they are caught, showing up again and again on bank cameras all over the country.

"There's not a whole lot of guys doing bank robberies," explained detective Dory, who keeps a drawer full of bank surveillance camera pictures and sometimes can identify a robber as soon as the film is developed.

One robber that Dory still is looking for is a man he calls "Bob Redskin." The robber got his nickname by robbing a Detroit bank while wearing a Washington Redskin's cap. Bob Redskin since has hit banks in Washington and other cities, but has not been seen in some time, leading lawmen to suspect he may have been caught somewhere. s

New York authorities recently picked up one of Dory's most-wanted men, a local resident named Johnny Ray Harris. Harris is charged with 13 robberies in New York and is being held for Washington police on charges that he robbed 11 banks here. Three Baltimore bank jobs also are blamed on him.

D.C. bank robbery detectives Charles Dunn and William Wagner had Harris handcuffed to a chair in their office two months ago. Vomiting while he went through withdrawal from herion, Harris admitted that he had pulled five Washington bank jobs and had tried unsuccuessfully to take two more to support his habit, Wagner said.

The detectives were preparing to close the case, but at a bond hearing D.C. Superior Court Judge Gladys Kessler released Harris on his own recognizance and ordered him to sign up for drug rehabilitation before his next court appearance.

But on the day Harris was supposed to show up in court, he allegedly tried instead to rob the American Security Bank branch at 3500 Georgia Ave. NW. He walked out penniless when a teller refused to honor his note.

Turning down a robber's demand for money violates the basic rules for being robbed, bank security specialists, police and FBI officials agree.

"We stress the importance of not doing anything to invite trouble," said Bob Croskery, security director of American Security Bank and a former Montgomery County lawman.

"If you have a teller who panics, you're going to have a really bad situation on your hands. The stress is on keeping calm. My concern is not so much the money as the safety of the personnel."

American Security has more branches than any other Washington bank and, as of a few days ago had had more robberies: nine successful one and three attempts, compared with two at this time last year and 10 for all of 1980.

The statistics are similar at National Bank of Washington, which has had five robberies so far this year, the same total as for all of last year, said Ed Mathews, vice president for security.

A bank robbery, especially one committed by a "counter jumper," has "a big impact on the customer and on the people in the bank," said Mathews, whose bank is cited by police as one of the most security-conscious in Washington.

"We do everything that we can to protect our customers and our people. We don't want any innocent victims among the ranks of our customers and we don't want innocent victims among the employes of the bank," Mathews said.

"If our people react with calmness, the customer is going to react the same way," added Ken Kling, who teaches NBW tellers how to be held up.

Kling said he tells the employes to "remain calm, be observant and try to remember everything you can."

Teaching bank employes to be good witnesses is vital, agrees Croskery. Multicolor stripes on doorways that help bank employes determine how tall a robber is are one visible sign of efforts to make identification of robbers easier.

One of the ways banks try to make robbery less lucrative is to reduce the amount of cash each teller has in the drawer. The typical note-passer only gets away with the cash from one teller, because the robber wants to avoid alerting the whole bank.

The velvet-rope rate mazes that banks use to speed customers to the first available teller also are touted by some as a minor deterrent to note-passers. Forcing the robber to wait in line makes the thief uneasy and makes it impossible to single out a teller who looks young and nervous or who is close to the door.

Many banks also equip each teller with special packets of money waiting to be stolen. Inside the stock of bills is a paper-thin, exploding pack of red dye that sometimes literally enables police to catch robbers "redhanded."

The bank detectives have other tricks that they won't talk about, but few answers to what makes people rob banks or how to reverse the alarming trend.

"It's difficult to discover anything we can do to stop them," said American Security's Croskery. "What we hope to do is minimize the chance of injury and keep the dollar loss down."

Bank robbery is "a subculture kind of thing," said Washington FBI chief Gardner, who says it often is possible to trace entire waves of robberies to groups from the same neighborhood, school or cellblock.

"What causes bank robberies? I don't know," says Gardner's counterpart in Baltimore, Ed Hegarty, "You're getting into sociology. You can't point your finger to any one thing."

D.C. detective Dory admits that he does not have the answer either, but he knows it is going to get worse.

"This is prime time for bank robbers," said Dory. "It's warm, school's out and unemployment is high."