Salvador Portillo-Saravia, a member of the MS-13 street gang, was charged with raping an 8-year-old girl at her Fairfax County home last month. But he never should have been in Fairfax in the first place.

Federal officials deported Portillo-Saravia, of Sterling, to El Salvador in 2003, and he sneaked back in illegally. Now, officials are wondering why a much-touted federal program didn't catch him before the rape.

Four weeks before the crime, Portillo-Saravia was in the Loudoun County jail for public intoxication. That's when the Immigration and Customs Enforcement (ICE) program, called Secure Communities, should have identified him as an illegal immigrant and he should have been taken into custody.

Loudoun authorities ran Portillo-Saravia's fingerprints through a federal database, but despite the 2003 deportation, nothing was found. He was released after 12 hours behind bars.

Portillo-Saravia, 29, is now the subject of a manhunt by local police and federal marshals.

Officials involved with Secure Communities and immigration experts said the incident points to confusion about how the program should work and to gaps in the immigration database. Many people who were deported before 2005, including Portillo-Saravia, are not in the fingerprint database, ICE officials said.

Jail officials in Virginia and Maryland who have relied on the program said they were not aware of the gap in the database.

"I was under the impression that everybody they had contact with was in the system," said Michael L. Wade, the sheriff in Henrico County, Va.

"Secure Communities is a very good program, but it's not a magic solution and shouldn't be sold that way," said Jessica Vaughan, a senior policy analyst at the Center for Immigration Studies, a Washington think tank that advocates tighter immigration controls. "This is why you do go after low-level offenders, because it can turn out they are a threat to public safety."

Secure Communities was rolled out in October 2008 amid much fanfare as a way to transform immigration enforcement, ICE officials said then. Jails would fingerprint all arrestees, not just those suspected of being in the country illegally. Those prints would run through FBI and Department of Homeland Security databases, and ICE would flag immigration offenders for possible deportation.

But it didn't work in Portillo-Saravia's case.

Loudoun jail deputies submitted Portillo-Saravia's fingerprints on Nov. 21 and received a "no match" message. Brian P. Hale, a spokesman for ICE, said Loudoun then should have done a manual record check or contacted ICE if the person was "foreign-born and of concern to local law enforcement."

Loudoun Sheriff Stephen Simpson was frustrated by Hale's response. Simpson said that ICE advertised the program as a way to electronically check all people arrested as soon as they are fingerprinted, eliminating the need for additional investigation.

"Nobody's ever heard of calling for a manual check," he said. "The point of the program was it replaced the need to do what they now say we should have done."

He added, "We did everything we were supposed to do."

If deputies investigate after a "no match," he said, "that's when we start getting ourselves in trouble" by raising the issue of racial profiling.

Other local officials agreed that it would be too much of a burden to do a manual check.

"Unless we hired an additional cadre of 20 to 50 deputies, it would be an impossible task," Fairfax County Sheriff Stan Barry said.

Said Mary Lou McDonough, director of the Prince George's County jail: "We process about 25,000 people a year. There's no way I'm going to second-guess" a "no match" result. "They either have a federal detainer or they don't. If they don't, they go."

Even though Portillo-Saravia had been deported, ICE officials said, he wasn't in their IDENT database, which has fingerprint and biometric data for more than 91 million people. Fingerprints before 2005 were taken the old-fashioned way, by rolling ink-stained fingertips on a card, ICE said, so people deported before 2005 may not be in the electronic system.

From 2001 to 2005, the United States deported more than 751,000 people, according to ICE statistics. ICE officials do not know how many of those people were fingerprinted manually and are not in the database.

Hale said that, as a result of the Portillo-Saravia case, ICE will send a reminder to all program participants that they should consider taking extra steps, such as requesting a manual records check or contacting ICE directly, if they receive a "no match" message but still suspect an immigration violation.

Simpson said he sent a letter to Homeland Security Secretary Janet Napolitano and Rep. Frank R. Wolf (R-Va.) calling for ICE to place an automatic detainer on all people who are deported, in case they return to the country.

Secure Communities is used by 986 jurisdictions in 38 states, including every jail in Virginia and the jails in Prince George's, Frederick, Queen Anne, St. Mary's and Anne Arundel counties in Maryland. It is not used in jails in the District. By 2013, ICE hopes to have the technology hooked up in jails nationwide, with the intent of detaining and deporting illegal immigrants convicted of crimes.

In slightly more than two years, jails nationwide have submitted 5.5 million sets of fingerprints through Secure Communities, resulting in the deportation of more than 58,000 people, according to ICE statistics.

The program remains controversial, with some law enforcement officials saying that the prospect of deportation discourages immigrants from cooperating with police or reporting crime.

Arlington is trying to remove itself from the program - Virginia State Police signed up the entire state in 2009 - because officials think it threatens public safety by promoting distrust between police and the immigrant community, the county's board declared in a resolution last fall.

Secure Communities overcame the concerns of some sheriffs, such as Simpson and Barry, by allowing checks of every arrestee, to avoid racial-profiling accusations. If an illegal immigrant was arrested in a serious crime, had a conviction or a pending detainer, or had been deported, ICE would notify the jail to hold him for pickup by immigration authorities when he was due to be released.

ICE said Portillo-Saravia illegally entered the country in 2000. He was deported in October 2003 after what ICE called an encounter with the Prince William police gang unit. It is not known when he reentered the country, but reentry is a federal offense.

When Portillo-Saravia was arrested Nov. 21 on a public intoxication charge, Simpson said, his department sent Portillo-Saravia's fingerprints to the ICE database.

"We never heard anything from them," he said. "By law, if we don't have anything to hold them on, then away they go. We didn't know any more about him than he was arrested. We had no reason to believe he was a gang member. There was no other reason for him to be on our radar screen. Why it didn't hit, I don't have a clue."

On Dec. 26, Portillo-Saravia was visiting a home on Cardigan Square in Centreville with a friend. Fairfax police said Portillo-Saravia's friend was dating a woman who lived there. The woman has an 8-year-old daughter.

Fairfax Detective Darrin DeCoster said Portillo-Saravia went to the girl's room and sexually assaulted her at 10:30 a.m., while other people were in the house. No one heard the attack, but the girl reported it to her mother that day, and "we do have evidence to support that allegation," DeCoster said.

Vaughan, of the Center for Immigration Studies, said the case "illustrates a number of the pros and cons of the Secure Communities program," such as that "ICE has not been giving the local users of Secure Communities enough information on how they should handle these 'no matches' when they happen. Leadership in that [ICE] office acts like it's apologetic, pandering, instead of getting out and using it more actively."

The fact that Portillo-Saravia's prints weren't in the database indicates that "maybe there is a large class of people who aren't," Vaughan said.

Vaughan, who said she studied gang and immigration issues closely in Northern Virginia in 2005 and 2006, said the Secure Communities program isn't clear on how jails should respond to a "no match" message. "Having Secure Communities doesn't relieve the local officers of the responsibility of asking foreign nationals questions," she said. "That's a policy choice the sheriff is making. But that may be a faulty impression based on what he got from ICE."

Michele Waslin, a senior policy analyst at the Immigration Policy Center, which has raised concerns about Secure Communities, said it was "ridiculous" for ICE to say Loudoun should have done further checks on Portillo-Saravia. "The fact is they did everything right, but he didn't appear."

Waslin added, "This is what they're pushing as the answer to everything. Clearly it's not. That's why it's important for police to have good relations with their communities, so people share information with them, maybe tell them who's not here legally. But if you're scaring everybody in the community, because they're afraid you're going to deport them, you're not going to get that information."