BISBEE - At shortly after 7 p.m. on June 7, U.S. Border Patrol Agent Richard Ramirez pulled over a vehicle driving north on Highway 80 near Tombstone.

According to an arrest report from the Tombstone Marshal's Office, Ramirez found three people in the car: the driver, Douglas resident Jesus Sierra and two passengers both suspected to be illegal immigrants.

Ramirez took the two passengers into custody but declined to arrest Sierra, despite the fact it's illegal under federal law to knowingly transport undocumented people within the United States. However, Tombstone Deputy Marshal Jose Olivas, who responded to the scene following the stop, arrested Sierra and charged him with violating the state's human smuggling statute.

A.R.S. 13-2319, better known as the "anti-coyote law," which was passed by the Arizona Legislature on Aug. 12, 2005, was the first state law to deal with the problem of human smuggling. The legislation arose in large part from Arizonans' frustrations that the federal government was not doing enough to enforce immigration law.

The arrest of Jesus Sierra illustrates the type of federal indifference that led to the law, said Cochise County Attorney Ed Rheinheimer, who expresses his own frustration at being handed cases that should be the domain of the U.S attorney.

"It is nothing new in Cochise County that people being stopped and arrested by federal law enforcement are not prosecuted by the feds," he said.

What is new, he continued, is that human smuggling has been added to the list of federal offenses that can be handed off to local law enforcement.

"This is just one more area where the federal government is not doing what it's supposed to be doing," Rheinheimer said.

Citing agency policy, Wyn Hornbuckle, spokesman for the U.S. Attorney's Office in Arizona, could not provide statistics on human smuggling prosecutions in the state. And the Border Patrol's Tucson Sector couldn't offer arrest numbers specific to Cochise County.

However, Border Patrol spokesman Jim Hawkins said that in the entire Tucson Sector, which includes all of Arizona's border region except for Yuma County, agents had made 4,659 human smuggling arrests during the first nine months of the current fiscal year, which began Oct. 1, 2006.

That figure represents an upward trend from the previous two fiscal years, when agents made 4,559 and 4,959 arrests over a 12-month span, Hawkins said.

Even so, it appears that agents, following instructions from the federal prosecutor's office, are still declining to arrest some small-scale human smugglers.

Asked about Ramirez's decision not to arrest Sierra, Tucson Sector spokesman Richard DeWitt said that agents make human smuggling arrests based on guidelines from the U.S. attorney - as well as the circumstances at hand.

For example, if a driver has endangered his or her passengers, an agent may decide to make an arrest, DeWitt said.

Otherwise, agents follow operational instructions determined by the federal prosecutor.

"It's typically a much larger load (of illegal immigrants), possibly with some type of organization behind it," that the U.S. attorney wants to prosecute, he said.

The concept of federal load thresholds is not new for state-level prosecutors, who say the U.S. attorney also declines to prosecute marijuana smuggling cases if the amount of pot is below 500 pounds.

And while the U.S. Attorney's Office denies using thresholds in narcotics cases, prosecutors in the drug unit of the County Attorney's Office say they get so many federal referrals that they have to decline most of them in order to focus on cases generated by local police.

"We have a dilemma here whether to absorb cases that are generated by federal law enforcement agencies," Rheinheimer said. "We don't have the manpower to be prosecuting (those cases)."

Tombstone Marshal Merlin Jay Smith said he just wants someone, whether it's the county attorney or the U.S attorney, to prosecute the human smugglers who use his town as a conduit for ferrying illegal immigrants.

And while it would be preferable for the Border Patrol to enforce immigration law, Smith said, "we just haven't seen a result" from federal efforts.

Therefore, he's instructed his deputies to start arresting drivers who are caught in Tombstone with illegal immigrants in their custody.

"We want to be a little more affirmative in how we deal with the problem rather than just making it a swinging door for these people," Smith said.

As for Jesus Sierra, the state human smuggling charges against him were dropped Monday after prosecutors failed to receive a complete report from the Tombstone Marshal's Office, Rheinheimer said.

The charges were dropped without prejudice, however, and could be filed again if the report surfaces with enough evidence for a prosecution.

There have yet to be any convictions in Cochise County under the state human smuggling law. Jose Alberto Chavez-Rojas, a native of Mazatlan, Mexico, is currently in custody at the county jail as he awaits trial on the charge.