The tour bus rounded Whitehurst Freeway en route to Georgetown and stopped where swanky M Street meets shady Canal Road.

"Remember the steps from 'The Exorcist' -- that's them," shouts a passenger as a few dozen necks crane for a view of the hillside stairway. Driver Harold Green confirms that the steps were the backdrop for the gruesome finale of the 1973 movie, then he congratulates his riders for knowing a few more tidbits about the nation's capital than his usual passengers.

They should.

In a month or two these "tourists" almost certainly will be asked to direct visitors to the most famous sights in town when they hit the streets as D.C. police officers.

They are graduating class "90 dash 6" of the D.C. Police Academy in Southwest Washington. They also are the fourth class to get a sightseer's tour of the city as part of their training.

The idea to let police recruits become tourists for an evening sprung from discussions in March between Police Chief Isaac Fulwood Jr. and Daniel E. Mobley, head of the Washington Convention and Visitors Association.

"We were talking about the fact that tourism is the second largest industry in the city," Mobley said. "This is a way to make officers more aware of that and let them have some fun."

Charles Cummings, general manager of Gold Line/Gray Line Tours, said his company donated the buses and guides. "We want to do good things for the police right now," he said. "They need a whole lot of help."

Officer Regina Forda said recruits need the tours partly because so many -- two thirds of the class of "90 dash 6" -- come from out of town.

The department regularly recruits coast to coast because of its shrinking pool of local applicants, said police spokesman Lt. Reginald Smith.

But even some local recruits are poorly informed about Washington's attractions, and some know little about things just across town, training officers said. "Some of these kids have never been downtown," said Officer M.J. Farish. "There are kids from one quadrant that have never been to another."

The tour includes the Capitol and Tidal Basin and all the other things out-of-towners typically see -- and more. Since many are minorities, we wanted to show them black Washington, too," Mobley said.

The reaction from the 32 fresh-faced recruits on tour last week was mixed. Some sat silently, engrossed by Green's details.

Others joked or buried their heads in the manual "Tactical Edge: Surviving High-Risk Patrol."

"We'll be driving through some areas where you'll be expected to maintain law and order," Green said as the bus drove onto South Capitol Street.

North on Martin Luther King Jr. Avenue, the bus made a quick fly by St. Elizabeths Hospital onto W Street SE and to the Frederick Douglass Memorial Home.

Outside, a knot of boys stopped playing ball and looked inquisitively at the busload of recruits.

At W and 16th streets, a family sitting on the lawn of a house with boarded up windows waved at the unfamiliar sight.

Across the 11th Street bridge, past the Mall and White House to the Capitol, Green motioned to the large flower pots blocking the Capitol's entrance, explaining that the pots actually are barricades.

"See that car," barked Sgt. J.L. Vincent from the front of the bus. "That's a ramming car. If anyone gets through those flower pots, it's his job to ram."

Past the Smithsonian, down Constitution Avenue to G and 20th streets NW, one recruit already was asking where Georgetown was.

When the bus arrived at the popular nightlife strip, Green blared the obvious: "A number of you may be assigned to Georgetown. You will notice there's quite a bit of activity here, especially on Friday and Saturday nights."

"Yuppie bashing, is that still going on here?" asked a recruit, referring to the recent assaults that have led police to restore some summer patrols there.

North on Wisconsin Avenue, past the Naval Observatory to Dupont Circle and Connecticut Avenue for a peek at "where John Hinckley tried to assassinate President Reagan," then the bus whizzed past the New Bethel Baptist Church.

"This is Walter Fauntroy's church," Green said.

"Who's Walter Fauntroy?" a recruit asked.

Back at the starting point, the recruits praised the tour as beneficial for their work ahead. A few even complained that it could have been more comprehensive. Robert Ingram, 22, and Steven Ellis, 23, said they wanted to see more of Northeast and Southeast.

But Michael Wright, 23, who moved to Washington a month ago from Harford County, Md., said the evening was helpful. "When I first got here I had a few tours of the city on my own -- by being lost," he said. "But I hadn't seen any of this stuff."