Topeka ? Calling it “a simple but serious mistake,” the head of the Kansas Bureau of Investigation said Thursday that a 12-year-old evidence error that was recently discovered was an aberration.

The statement from Larry Welch, director of the KBI, came a day after he apologized for the mislabeling of a blood sample in October 1991 and acknowledged it led to a significant delay in identifying Douglas S. Belt as a suspect in a rape in McPherson County. Welch said Thursday that he was confident there was not a widespread problem with evidence at the agency’s labs.

He also acknowledged that other crimes for which Belt has been charged might not have occurred had the evidence been properly handled.

“It is quite possible that we could have prevented some of those crimes, had the mistake not been made,” Welch said during a news conference.

Belt is being held in Sedgwick County on a first-degree murder charge for the June 2002 death and decapitation of Lucille Gallegos, 43, at the Wichita apartment complex where she worked as a maid. Belt, a 42-year-old truck driver in Wichita, also is charged with several rapes in Kansas and with sexual assault in Illinois.

Welch said that while victims and their families had been understanding, he expected lawsuits to be filed against the KBI over crimes that occurred after the 1991 error.

The mistake was discovered in December when a new DNA sample taken from Belt after his arrest in the murder matched the blood evidence from the 1991 rape as well as evidence in other rapes.

Welch said the error occurred at the KBI’s Great Bend lab. An employee, who still is on the job, mismarked evidence from a second suspect as belonging to Belt. As a result, nobody was charged with the rape.

The error was made public after Atty. Gen. Phill Kline learned of an internal review that found the mistake and ordered Welch to make the information public. On Thursday, Kline ordered an outside audit of KBI lab procedures, as well as a review of current case files to ensure accurate handling of evidence.

“These steps are necessary and will strengthen public trust and confidence,” Kline said in a written statement.

Welch said the KBI lab was due for national reaccreditation in September, but he does not expect the 1991 mistake to affect that status. He did not know how quickly the outside audit would be completed.

The lab, which was nationally accredited in 1998, has changed how it handles evidence since 1991.

Months after his arrest on the murder charge last November, Belt was charged with seven rapes that took place between 1989 and 1994 in four Kansas counties.

Belt also was charged Dec. 20 in Madison County, Ill., with three counts of aggravated criminal sexual assault stemming from a Nov. 22, 1992, attack on a 21-year-old mother of two near Granite City, Ill.

According to the Department of Corrections, Belt was convicted three times on theft, burglary and drug charges between October 1995 and March 1999.

As a convicted felon, Belt submitted a DNA sample in January 2002, which as of earlier this week had not been processed, the KBI said.

Welch said the Kansas lab was not unlike other state labs that are overwhelmed with a backlog of evidence to process, including more than 20,000 samples of DNA from convicted felons awaiting cataloging.