The conflicting priorities of the Los Angeles Police Department and federal immigration officials have created a law enforcement gap that has hampered efforts to crack down on human smugglers, according to city and law enforcement officials.

The division came to the surface in a widely publicized raid in which police discovered 110 illegal immigrants being held against their will at a Watts bungalow. In the aftermath last week, officials with both the local police and the federal immigration agency said the other group could do more to combat smuggling.

Both sides have agreed to meet this week to discuss their differences and to work on ways to operate more cooperatively. The history of the two agencies, however, could work against them.

The LAPD is usually the first to get calls about immigrants being held against their will at safe houses. But the department must walk a fine line. For more than a decade it has tried to keep at arm's length from immigration officials.

When the LAPD has gotten close to immigration agencies, it has paid a political price, as happened during the Rampart scandal when the LAPD was accused of seeking to have witnesses to police misconduct deported. Police have tried to boost credibility in immigrant communities by making clear that they work independently of the INS's successor agency, the U.S. Bureau of Immigration and Customs Enforcement.

As for immigration officials, their workload has increased since the 9/11 attacks. LAPD commanders as well as Los Angeles Councilwoman Janice Hahn said that investigating safe houses, particularly when the numbers are small, has become a lower priority for the immigration bureau. Hahn said that federal officials were "abdicating" their responsibility, a charge the bureau denied.

Southern California has become a central port for human smuggling, in part because residents who live in neighborhoods where the safe houses are located often look the other way for fear that calling authorities might hurt the immigrants. The Watts house, for example, operated for two years before police found out about it.

Often, Mexicans or Central Americans start their journey across the U.S. border as clients -- paying between $1,000 and $10,000 -- but wind up captives of coyotes, or smugglers, who hold them in places like the Watts house until family members pay additional ransom.

Police and federal authorities agree that when human suffering or serious crimes like rape or kidnapping are involved, both agencies should investigate, capture and help prosecute smugglers.

The rub is how to deal with the people who have hired these smugglers.

When the LAPD handles a smuggling case on its own, the immigrants are usually released. When the bureau is involved, it's much more likely that the immigrants will be deported.

Los Angeles police have a long-standing policy, called Special Order 40, that bars officers from informing federal immigration officials about undocumented immigrants they discover during the normal course of their duties. The purpose of the order, which was adopted by the Police Department in 1979, is to assuage illegal immigrants' fears that they may be detained or deported if they seek assistance from local law enforcement.

"We want our residents who are immigrants to know that they can have contact with the LAPD without being referred to" federal immigration officials, said Los Angeles Police Commission President David Cunningham III. He said that when police agencies act as an immigration enforcer, "it has a chilling effect on the reporting of crimes in immigrant communities."

That sentiment is shared by some immigrant-rights advocates.

"Local law enforcement should never be an arm of the federal government in immigration matters," said Luis Carrillo, a civil rights attorney who has represented illegal immigrants in cases involving police.

But immigration agents said that police officers occasionally misinterpret the rule and apply it too readily.

Virginia Kice, a spokeswoman for the immigration bureau, suggested that law enforcement agencies may need to update their policies on immigration enforcement.

"Everyone recognizes that it is important for local law enforcement to maintain credibility and the confidence of the entire community, including the immigrant community," Kice said. "They don't want to do anything that jeopardizes that confidence by appearing to work too closely with immigration."

But, she said, "times change, and maybe the strategy needs to change." Kice noted that local and federal law enforcement agencies in Phoenix reported a decline in smuggling operations after intensifying their collaboration.

The LAPD and the bureau have worked together on many raids of large smuggling rings, including the one in Watts. LAPD officials, however, suggested that federal officials appeared interested in only the bigger rings.

Police said that after Sept. 11, immigration officials got involved in relatively few smuggling cases. The bureau has become more involved in recent months, agency officials say, but the relationship between the two agencies still isn't perfect.

Los Angeles Police Capt. Al Michelena cited an example of the bureau's lack of interest in smaller rings, referring to an incident in South Los Angeles last month. There were two safe houses, one of which held 19 illegal immigrants and the other 18. Immigration officials came and documented the immigrants and then released them because they did not have facilities to hold them, he said.

Immigration officials strongly deny that their focus on terrorism has lessened their resolve on human smuggling. They respond that the LAPD often gets the first call on smuggling rings, and if the bureau isn't involved, it may be because police choose not to inform the agency.

"As large as our area is, we'll break up some operations independently, but local law enforcement really needs to have their antenna up," Kice said. "The fact is, there's a lot more LAPD officers out in the streets than ICE agents."

Hahn expressed hope that a meeting between the two departments could improve communications.

Professor Niels Frenzen, an expert on immigration policies at the University of Southern California Law School, said the fact that the Watts safe house operated for two years before detection "is a pretty sad commentary about people not watching out for their neighbors."

"I also look at it this way: People don't think that it's necessarily a positive thing to bring law enforcement in on these issues," said Frenzen. "One reason for that could be because of bad experiences they've had with law enforcement. But there are probably situations where neighbors know what is going on, but also know full well that if they pick up the phone to help these individuals, these individuals are going to get arrested and possibly deported."