Thousands of folders crowd a wall of double-sided shelves at the Sheriff Al Cannon Detention Center, a small mountain of paperwork devoted to a host of slippery suspects who went off the grid before they could be arrested.

The folders contain arrest warrants for a cornucopia of offenses, from missed court dates to rapes and murders. Some date back weeks; others, as many as 30 years. They await the day when the suspects in question resurface or cross the paths of law enforcement officers who find their names flagged for arrest.

A recently discovered mistake in the processing of one of those warrants helped a man accused of sexually assaulting a young girl avoid arrest for 15 years before his capture last week. During his time on the lam, he became a foster parent, authorities said.

"There is no defense for this," Charleston County Assistant Sheriff Mitch Lucas said Tuesday. "We just made a mistake."

The slip-up has sparked an exhaustive audit by deputies, who are rechecking the status of 28,604 unserved warrants for potential errors, Lucas said.

A check on those pertaining to serious felonies produced 26 unserved arrest warrants from 1982 to 2002 that were not properly entered into the FBI's National Crime Information Center database, a nationwide clearinghouse of data on wanted suspects. That means the suspects wouldn't show up as wanted for those crimes if they were stopped by police.

Among that lot is a warrant from a 1983 murder in which the suspect, an illegal immigrant, likely fled the country, Lucas said.

The search also has turned up 10 improperly entered warrants issued for felony suspects who didn't show up for court dates, he said.

A team of seven deputies has been assigned to review the cases in question, assess where they stand for prosecution and try to find the wanted suspects, Lucas said.

Failure to enter Travis Kilgo's warrant in the NCIC database helped the 50-year-old Florida man evade arrest for 15 years on a charge of criminal sexual conduct with a minor under the age of 11, sheriff's officials said. The charge stemmed from his alleged molestation of a girl on Johns Island between 1988 and 1991, starting when she was 4 years old, an affidavit states.

Deputies learned of the allegations in November 1997 and obtained an arrest warrant the following April, but Kilgo already had skipped town for the Sunshine State after he reportedly confessed to the girl's father, authorities said.

The warrant went unserved and unnoticed until deputies discovered it during a recent review, Lucas said.

Deputies quickly located Kilgo in Florida and arrested him within 24 hours of discovering the warrant. He implicated himself in the crime when confronted by deputies and is now in the county jail, Lucas said.

Kilgo insisted he had committed no crimes in the years he was wanted, and investigators found no evidence to contradict him here or in Florida, Lucas said.

Kilgo applied for and received permission to become a foster parent to his three grandchildren in 2000 in Florida, with no red flags raised because the warrant had slipped through the cracks, Lucas said. An extensive review concluded that no harm had come to those children as a result, he said.

Investigators also found no evidence that Kilgo had signed up as a Scout leader, coach or some other position that would have put him in close contact with children, Lucas said.

Lucas said the alleged victim of the 1997 sexual assault, now a grown woman living in California, was notified of the slip-up and Kilgo's subsequent arrest. She also knows of no other victims, he said.

"We are as confident as we can be that there are no more victims," he said.

Ninth Circuit Solicitor Scarlett Wilson said she can't say how greatly the delay in Kilgo's arrest will affect the prosecution of the case until her office has reviewed the evidence in its entirety. "We do not have it yet," she said.

Lucas said the mistake went unnoticed for so long due to the heavy volume of warrants flowing into the Sheriff's Office, which had a backlog of 43,000 warrants just a few years back. A general decline in crime, the Solicitor's Office's decision to manage the voluminous case-load for bad-check warrants and other factors helped reduce the deluge of work for deputies in recent years, officials said.

The number of incoming warrants dropped from an average of 754 per month in 2010 to about 545 per month this year, Lucas said. That gave deputies in the warrants unit some breathing room to do a more intensive, in-depth review of the backlog, he said. Technology improvements and the creation of a new warrants database have aided that effort.

"We're correcting a lot of mistakes that may have happened 10 or 15 years ago because the technology wasn't available to us then," Maj. Eric Watson said. "It will address the backlog of warrants."

Lucas said about 100,000 warrants had passed through the Sheriff's Office since Kilgo's warrant was filed, Lucas said. Given that volume, Lucas said, he was surprised more mistakes were not found beyond the 26 warrants identified.

The audit is expected to continue for the next 90 days, with a team of deputies checking each warrant to make sure it is still valid and has been entered properly in the national database, Lucas said.

"It's daunting, but it needs to be done and we're doing it," sheriff's Capt. Tim Huey, who oversees the warrants unit, said. "It's important, because there might be victims out there who need their day in court."

Reach Glenn Smith at 937-5556 or