Nobody knows the exact number of crimes committed by illegal aliens in the Salt Lake area, but anyone who examines the clues knows the figure is significant.

That became clear when the Utah Federal Immigration Prosecution Project began in 1997. The project used a beefed-up presence by the Immigration and Naturalization Service and other federal resources to double-check fingerprints and examine inmates in county jails and the state prison. So far, it has indicted 484 suspected dangerous illegal immigrants. More than 200 of those indictments have been attained this year alone.When the City Council considers whether to grant limited INS authority to 20 city police officers in coming weeks, it can hardly overlook those figures. Nor can it overlook the heinous nature of many of the crimes these people commit. Police still are searching for Mario Peraza-Armenta, for instance. He is a Mexican national wanted in connection with the brutal murder of Diane Purper, the mother of five who was killed while entering an I-15 onramp on Feb. 3, 1996.

While Purper's death attracted a lot of attention, illegal aliens are responsible for many other deaths along the Wasatch Front, as well. The unfortunate fact is that many of the suspects have been in custody at various times but have not been identified. Peraza-Armenta, for instance, had been jailed several times under several different assumed names before Purper was killed.

The City Council has decided to hold a public hearing before making its decision. That's prudent. But public testimony shouldn't override strong arguments in favor of this added power. If the city agrees to turn 20 officers into quasi INS agents, the public would have another tool in the fight against this dangerous element. As it is, officers who now arrest suspected illegal aliens have to wait for an INS agent to arrive and process the suspect. Often, that never happens because INS agents are unavailable.

Some council members, as well as some members of the public, worry this would give city police a license to be racist. People of color, they say, would be detained simply because of the way they look. This is no small concern, but there is scant reason to believe police would act this way.

The program would allow police to adequately handle people they already are detaining as suspects in crimes. City residents have no reason to believe police would go further than that, stopping people without probable cause. Such behavior is particularly unlikely considering the police chief, Ruben Ortega, is himself Hispanic.

Any allegations of police racism should be investigated immediately and thoroughly. But set aside race for a moment. No one can credibly deny that a group of illegal aliens is posing a significant risk to the local population. Federal officials say crackdowns send a strong message that reverberates back to the Mexican homeland where many of these criminals are spawned.

That message is to stay away from Utah, and for the good of law-abiding residents of all colors it ought to be sent as clearly and forcefully as possible.