The Arlington County police officer was investigating a grocery store robbery when she discovered that the clerk didn't speak English, but she pressed on without missing a beat.

"Que paso?" asked Officer Adrienne Pheil, inquiring what happened and learning that a man with a gun had taken a fistful of money from the cash register. She went on to ask the clerk whether he had been hit and if he was hurt. "Le pego? Esta herido?"

The interview went smoothly until Pheil had to ask more complicated questions about the cash register. "Senor, esta, eh, did he touch it?" Pheil inquired, unaware that she had switched languages.

The interview, about a robbery that never happened, was staged last week at the Northern Virginia Criminal Justice Academy in Sterling, but it represented a turning point for Pheil, who a week earlier could barely say "hello" in Spanish.

Pheil was one of 15 officers from various Washington area police departments, including Alexandria, Loudoun and the Metropolitan Washington Transit Authority, who took the special Spanish language course designed for law enforcement.

"She's getting so comfortable with the [Spanish], she said things in English without realizing it," said instructor Mike Berg, a Herndon police officer. Her fellow students included Officer Bond Shaw, of the Leesburg Police Department, and an undercover officer with the Loudoun County Sheriff's Office.

Unlike high school or college Spanish courses, the intensive, week-long course teaches officers basic vocabulary and grammar geared toward police work, material that is not offered elsewhere.

The focus of the course is to teach officers to do rudimentary interviews of victims and witnesses and give commands in Spanish when a suspect is apprehended, said Robin Runser, spokeswoman for the Herndon police department, which conducts the course.

One of the students, Arlington police officer Heather Meeker, recalled her frustration when she encountered witnesses, victims or suspects who spoke no English. "You had to wait for a translator," she said, "but now I can talk to them and interview them and do it quickly so I can get the information out and help" investigate a crime.

The program began shortly after Berg, now a 13-year veteran of the force, completed a Spanish-immersion course offered by the Federal Law Enforcement Training Academy. The Herndon chief asked him to create a local curriculum. When Berg and Herndon police officer Larry Hildner began teaching Spanish to other Herndon officers in 1998, it became Virginia's first and only ongoing Spanish-immersion course taught by police officers.

Word about the Herndon program spread to the region's other agencies, whose officers were looking for Spanish instruction that would help them in their work without having to take extensive time off. Within three months, Berg and Hildner found themselves teaching Spanish to officers from all over the Washington area.

The demand for the course reflects the growing Hispanic population. Police officials say they are encountering more Spanish speakers in their daily rounds. Latinos, the largest growing immigrant community in the region, now account for about 10 percent of the population, about double the number in 1980.

In 1990, only about 2,000 people in Loudoun County spoke Spanish at home. But since then, the county's population has skyrocketed nearly 70 percent, and officials agree that the Spanish-speaking population has grown right along with the rest of the county.

As recently as five years ago, Leesburg had a relatively small Hispanic population, said Mike McVeigh, the town's acting police chief. Now, he said, large numbers of Hispanics live in town and work in local commercial areas.

The ability to speak Spanish has become a "very big plus" when the department is looking at job applicants, McVeigh said. The department has about six officers and several dispatchers who speak Spanish. At least one Spanish-speaking officer is available at all times to translate when needed.

During the last year, 200 police officers, corrections officers and dispatchers from 17 different jurisdictions have completed the course. Berg and Hildner with the help of Jorge Rochac, a Herndon resident who volunteers as a translator, now teach the course six times a year. Besides attending class from 7 a.m. to 3:30 p.m. each day, the students also are required to do several hours of homework.

"It's hard, but it's fun," Pheil said. "I've had to do homework while working out on the treadmill at home."

During the first few days, students learn basic vocabulary and grammar related to police work, such as giving directions, getting descriptions of people and interviewing victims and suspects. At the end of the week, the students interview role-playing victims and conduct simulated traffic stops entirely in Spanish, with Berg, Hildner and Rochac acting as the victims and suspects.

Meeker played the responding officer in such a mock felony car stop. "Abra la ventana," she said, telling the "driver" to open the window. "Apague el carro," she added, and the driver obliged by turning off the car engine.

With a flurry of instructions--albeit in less-than-perfect Spanish--Meeker had the driver face down on the ground, arms spread out and legs crossed. "Tiene armas?" she asked, making sure he had no weapons.

These basic skills are the focus of the course, Hildner said. It is not intended to teach officers to be fluent in Spanish but rather to give the officers the confidence to continue learning the language and "get by" when they encounter a Spanish-speaker.

"We can't teach Spanish in a week," said Hildner, who is a motorcycle officer; Berg is a canine handler. "We're trying to build confidence so they can learn more Spanish and talk to people who can't speak English."

Staff writer Tomoko Hosaka contributed to this report.

CAPTION: Mike Berg, a Spanish-language instructor, takes questions from officers at the Northern Virginia Criminal Justice Academy.

CAPTION: Arlington police officer Adrienne Pheil, right, conducts an interview in Spanish with mock robbery victim Jorge Rochac, a Spanish-speaking volunteer from Herndon. Pheil took part in Spanish language training with other Northern Virginia officers last week using the textbook below.

CAPTION: Keith Crane, left, and Heather Meeker listen to instructions in Spanish during the language training course to learn the basic commands needed for law enforcement.