Halloween on Hollywood Blvd. : Public Safety: Those people dressed up like police officers? They’re the real thing--all 400 of them.

More than 400 police officers will stake out Hollywood Boulevard next Tuesday on Halloween night in an effort to prevent a repeat of a melee last year that injured six people and damaged a dozen businesses.

The traditional but unofficial Halloween celebration is expected to attract 100,000 revelers to a 15-block stretch of the boulevard, police said. A crowd of similar size last year became unruly late in the evening when several dozen people began tossing bottles at police, smashing windows and looting stores.

About 170 police officers in riot gear, joined by mounted units and two helicopters, spent two hours restoring order near the intersection of Hollywood and Vine Street. Authorities arrested 28 people on charges ranging from drinking in public to assault on a police officer.

This year, the Los Angeles Police Department will more than double its street presence with officers on foot, in patrol cars, on horseback and on motorcycles. They will be deployed from SWAT, gang and narcotics units as well as detectives and other non-uniformed officers from divisions throughout the city. By comparison, the department deploys nine officers on Hollywood Boulevard on a typical Tuesday night.

“Those coming to Hollywood to have a good time, will have a good time,” Hollywood Division Sgt. Rod Bernsen said Tuesday. “Those coming to Hollywood to cause trouble will be going to jail.”

Even with the additional officers, some merchants said they fear a repeat of last year. Hassan Ebrahim, owner of British Imports, which sells leather goods and other heavy metal music accessories, said he may hire private security guards and board up the front of his store.

“If this time they do something to me, that is it. I am out of business,” said Ebrahim, who estimated his losses of last year at $130,000.

Even the Hollywood Chamber of Commerce, which normally takes every opportunity to promote shopping and tourism, is not promoting Halloween night on the boulevard. There are no parades or other organized activities planned for the evening.

The chamber on Monday mailed 1,800 flyers to its members detailing the police protection and predicting “a rather copacetic Halloween.” But chamber President Larry Kaplan said in an interview that no one can know for sure.

“After last year, we basically would not want to encourage people to come,” he said. “We would like to encourage law-abiding people, but who knows what is going to happen?”