May 27, 2010— -- Crime has been the central issue in the battle over Arizona's controversial new immigration law. Arizona Sheriff's Deputy Keith Henry is on the front lines, and he says human smuggling over the border from Mexico is rampant.
"It's huge," Henry said. "It's pretty bad out here."
The results can be seen in Arizona's prisons. According to the Arizona Department of Corrections, nearly 14 percent of all inmates in Arizona prisons are in this country illegally.
But it's more complicated than it looks. A survey by ABC News of federal and local law enforcement agencies on the U.S. side of the 2,000 mile long border with Mexico found that the rate of violent crimes is on the decline. In Tucson, crimes like murder, rape and assault declined 16 percent from last year. In Laredo, Texas those crimes are down four percent.
Police Sgt. Clint Norred patrols the Arizona town of Yuma.
"For the past five years, the crime rate has been relatively the same," he said.
But several high-profile cases -- including the murder of an Arizona rancher -- have kept crime at the forefront of the immigration debate. That killing was critical in the passage of Arizona's new immigration law.
The Arizona law requires police in the state to ask people for their documents if they have "reasonable suspicions" about their immigration status. The law will go into effect July 29 unless legal challenges stop it.
President Barack Obama, who opposes the law, renewed his opposition today at a news conference, but he fell short of supporting the decision of states like California to boycott Arizona. He said the decision to boycott is the decision of a private person, not a president.
The President's criticism comes a day after eight police chiefs from around the nation met with Attorney General Eric Holder to voice their complaints against the law. The police said that the law would turn them into border patrol officers.
Tucson police chief Roberto Villasenor said the Arizona law could reverse recent declines in violent and property crimes.
"When you enact legislation that makes any subset of that community feel like they are being targeted specifically or have concerns about coming forward and talking to police, that damages our capability to obtain information to solve the crimes," Villasenor said to reporters in Washington.
Arizona Immigration Law: Mayor vs. Mayor
Back in Arizona, two mayors take two different sides on the state's new law. Their towns are two miles apart, but their views on the law are nowhere near each other.
"There's a strong feeling that it's designed to protect the citizens and to prevent further breaking of the law," said Boyd Dunn, the mayor of Chandler.
Dunn supports the controversial law. He says that there's a connection between crime and illegal immigration.
"We've had shootouts on the freeway near our city between drug smugglers," Dunn said.
Meanwhile Yolanda Solarez takes the opposite view. She is the mayor of Guadalupe, a largely Latino town.
"I feel that it would target," she said. "Especially the Latino community."
The U.S. Justice Department warns that the law could lead to targeting people based on race too. It is mulling a legal challenge to the law.
A team of Justice Department attorneys drafted a recommendation saying that the law impedes the federal government's ability to enforce immigration laws. Attorney General Holder said that a decision will be made soon on whether the federal government will challenge the law.
In Arizona, Cesar Payan, a construction worker who's lived here illegally for 10 years, said that weeks before the law takes effect, it's already affecting crime.
He said someone broke into his car last week, but he didn't call police. He was too afraid.
The Associated Press contributed to this report.