At the Sentinel Rest Area in the middle of a different desert, Haab didn't find any Muslims or Arabs, but he did see brown people. And Haab followed the seven men to a vehicle parked at the rest stop, pointed his gun at them and ordered them out of the car and onto the ground. Haab then called 911.

After spinning numerous tales, Haab eventually admitted that the unarmed men had neither touched nor threatened him, and the Maricopa County Sheriff's Department arrested and charged Haab with seven counts of aggravated assault. In the words of the local sheriff, "You don't pull guns on people because of the color of their skin."

Less than two weeks later, however, Maricopa County Attorney Andrew Thomas drew a very different conclusion about the incident: Haab hadn't committed a crime, but rather a public service -- a citizen's arrest of seven men who apparently were transporting or conspiring to transport undocumented immigrants. He dropped all charges against Haab.

While Thomas claims to have engaged in a "full analysis of the issues involved and the applicable law," some civil rights advocates believe that his decision was based on something quite different -- his campaign promise to fight illegal immigration. After a close look at the relevant statutes, it appears the Harvard law graduate may well have disregarded some basic issues of law.

Felony or Fiction?
Arizona law allows for citizen's arrest when the suspect commits a felony that the arresting citizen witnesses or when a citizen knows that a felony has been committed and has reasonable grounds to believe that the suspect committed it. [See A.R.S. section 13-3884.] (The statute also permits an arrest for a breach of the peace, a claim not raised by Thomas).

According to Thomas, the felonies committed in Haab's presence were violations of a federal provision against "knowing or reckless" transport of undocumented immigrants and conspiring to transport undocumented immigrants within the United States. [See 8 U.S.C. section 1324 (a)(1)(A)(ii) and (v)(I).] Thomas argued that the coyote -- the person who transported the immigrants-- was committing a federal felony by transporting the men. He also asserted that the undocumented immigrants were committing a federal felony by conspiring with the coyote to have themselves transported.

Thomas' cursory explanation, however, leaves some obvious gaping holes.

First, federal law does not allow citizens' arrests in cases dealing with the transport of undocumented immigrants. The relevant federal provision specifies that "no officer or person shall have authority to make any arrests" pursuant to the statute, other than officers and employees of the Immigration and Naturalization Service and "all other officers whose duty it is to enforce criminal laws." [See 8 U.S.C. section 1324 (3)(B)(c).] Haab was neither an INS "officer" nor an "officer" with any other law enforcement agency.

Second, under section 8 U.S.C. section 1324, an undocumented person cannot be prosecuted for conspiring to transport him- or herself within the United States; only the person who is responsible for the transportation -- the coyote -- can be charged with a felony. [See Campbell v. U.S., 47 F.2d 70, 71-72 (5th Cir. 1931); Emmanuel v. U.S., 24 F.2d 905, 906 (5th Cir. 1928).] Because the men Haab detained were not violating federal law, he had no grounds to "arrest" them.

To make matters worse, Thomas has already signaled that he'll take an expansive view of a new Arizona statute. The Arizona legislature recently enacted a state law that makes it a felony to "intentionally engage in the smuggling of human beings for profit." Thomas interprets the statute to authorize the prosecution of immigrants who agree to be transported as conspirators, ignoring the fact that federal law comes to the opposite conclusion. [See A.R.S. section 13-2319; Maricopa County Attorney News Release, Opinion # 2005-002.] Although Haab cannot invoke section 13-2319 to legitimize his conduct because the statute did not go into effect until August 2005, other citizens may use it to justify detaining individuals they suspect are undocumented immigrants.

Prosecutors must have discretion to make judgment calls about which cases to prosecute. But it is difficult to ignore the implications of prosecutorial inaction in these types of cases. Whether motivated by politics or an incompetent legal analysis, Andrew Thomas' decision to drop the aggravated assault charges against Patrick Haab gives license to vigilante justice by armed, frustrated, private citizens guided only by racial and ethnic stereotypes and limited information. The role of government is to defuse such volatile situations, not fuel them.

Catherine E. Smith is an assistant professor at the University of Denver's Sturm College of Law, where she teaches a course on extremism and the law.