Stripped of a powerful tool in the fight against illegal immigration, Arizona prosecutors say they will rely on such standard tactics as wire taps and surveillance to crack down on human traffickers as the annual surge in smuggling begins this week.

A judge ruled last week that state prosecutors have no right to seize money transfers into Mexico from other states — cash that investigators suspect pays for human trafficking. Such seizures violate constitutional protections on interstate and international commerce, the judge said, adding that prosecutors failed to show that the wire transfer customers were committing crimes.

Arizona Attorney General Terry Goddard said his office will use other means to combat smuggling, but he added that nothing will prove as effective as the ability to seize money transfers with special court orders known as "damming warrants."

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The name comes from the attempt to "dam" up all wire transfers meeting certain criteria until the person to whom the money is being sent can show the cash is for a legal purpose.

Armed with such warrants, authorities have seized $17 million in money transfers into Arizona and arrested of more than 100 smugglers, he said.

"Nothing has been as effective as the damming warrants," Goddard said. "I believe that it is a very, very strong tool. Frankly, our fight against coyotes (smugglers) will be retarded if we cannot use them."

Goddard has said he intends to appeal last week's court decision.

The judge's ruling was particularly stinging because the heaviest flow of illegal border-crossers into Arizona is expected to begin this week.

In past two years, the Border Patrol made nearly half of all its arrests along the southern border during the first four months of the year, reflecting a pattern that agents say they have noticed during the past decade.

Most border-crossers are taking advantage of cooler temperatures in their pursuit of seasonal agricultural work, construction positions and other jobs in the underground labor market. Some are returning from extended holiday visits with families in their native countries.

Prosecutors can still seek court orders to seize money transfers into Arizona that are suspected of being smuggler payments. But that approach is of little use because payments to traffickers are being routed from other states into Mexico, Goddard said.

Alonzo Pena, the chief of investigations for Immigration and Customs Enforcement in Arizona, said the agency is examining the possibility of using federal subpoena power to track suspected smuggling money flowing into Mexico.

State and local authorities in Arizona have tried to diminish its standing as the country's busiest illegal entry point by rejecting the notion that immigration enforcement rests solely with the federal government.

Maricopa County has prosecuted immigrants as conspirators under a state immigrant smuggling law adopted 17 months ago. County Attorney Andrew Thomas said he has won more than 160 convictions under the law. Most of those who were convicted were the customers of smugglers.