The creators of "Contract on Cherry Street," a three-hour crime movie on NBC tonight, have found a new way to have their violence and not have it, too: They simply make the victims of shootings disappear into dead air.

At least a dozen fatalities punctuate the film (at 8 o'clock on Channel 4), but not all result in corpses. Sometimes the director cuts from a shot of the cowering target to a shot of the killer firing the gun and then, nothing.

Nothing except a commercial.

This may have been considered by the producers a clever way to get around the new sensitivity to TV violence, but it has an undesirable effect. The victims become like white blips in a TV pong game; one zap and they're gone from the screen. If anything, this kind of violence is more desensitizing than gushes of blood.

"Cherry Steet" is the first TV. movie for Frank Sinatra, who plays Inspector Frank Hovannes. After about 90 minutes of gratuitous plot meanderings, the story becomes a variation on "Death Wish." Hovannes discovers that one of his detectives is promoting a gang war by bumping off gangsters and a police informer - and finally even a fellow policeman.

By the end of the film, most of the jmajor characters are dead, but "Cherry Street" is not a daring kind of TV downer because it remains essentially pointless. It is also, at three hours, on hour too long.

Sinatra's rat pack of crony cops has been made carefully multiethnic; a Jew, an Italian, a Spanish-American. There are no blacks in his inner circle, however. Blacks on the other hand, are well represented in the film's depiction of the underworld, whom Sinatra finally blows away with a double-barrelled shotgun.

The film, written by Edward Anhalt and directed by William A. Graham, has interludes of peace which tend to be numbungly monotonous, so that one feels perversely encourages to look forward to the violence. To its credit, the movie was filmed on location in New York, and Anhalt has included a few thoughtful scenes about how the wives of the policemen react to their roles and those of their husbands.

Sinatra strolls through it casually, sounding most comfortable with lines like, "Now get outta here," Get over here," and "Beat it, get outta here."

He is supported and outacted by Johnny Barnes, dazzling as Otis Washington; Martin Balsam, touching as Ernie Weinberg; and Michael Nouri, who is decidely adept at catching the camera's eye and keeping it.

Unfortunately, all of them are dispatched to oblivion before this unsavory ordeal lopes to a close.