Updated

Wichita police arrested a "person of interest" in the BTK serial killer (search) case Friday, turning him over to the FBI for questioning.

Wichita Mayor Carlos Mayans (search) told reporters that there would be a news conference at 11 a.m. ET Saturday on the case, but he would not comment any further. Police sources, however, told FOX News they were "confident" that the person of interest was the man they were looking for.

A preliminary test matched the person in custody's genetic makeup to the DNA left by the BTK killer at some of the crime scenes, sources said. At the scene of a 1974 crime, sperm was found on and around the body of an 11-year-old girl. More detailed genetic tests are ongoing.

The man was arrested in suburban Park City, just north of Wichita, and his home was subsequently searched. Police made the arrest near where one of the BTK killer's recent packages was left.

Sources said police pinpointed the man by keeping an eye on areas they believed the BTK killer might go based on leads they received. Once they saw a vehicle drive into one of those places, they ran a license plate check, which helped them find their person of interest.

Authorities considered him a person of interest in the 1980s, but did not resume investigating him until recently. He is married and 59 year old.

The person of interest, who works in the code enforcement department for Park City, graduated from Wichita State University (search) in 1979 with a degree in administrative justice. Detectives believe the BTK killer has ties to Wichita State because some of the communications from him were copied on machines at the university.

Furthermore, one missive from the BTK killer, in which one of the murders was described, included a variation on a poem entitled "Oh Death." The poem was on the syllabus in a class taught by Wichita State professor P.J. Wyatt, and authorities believe the person of interest took a class from Wyatt.

In an interview during On the Record With Greta Van Susteren, Gary Vandusen, a neighbor of the person of interest, was surprised to learn of the recent developments.

"I was really shocked," said Vandusen. "It was unbelievable to me because I would never have suspected this in a million years."

Vandusen described his relationship with the man as cordial and neighborly, saying they would often talk about the rising crime rate in Wichita. But Vandusen added that other neighbors didn't seem to get along with the man.

They didn't like him because "he'd always have something to complain about," Vandusen said.

The BTK killer — the initials of the killer's self-coined nickname stand for "Bind, Torture, Kill" — has been linked to eight unsolved killings, committed between 1974 and 1986.

Police said they would make an announcement about their activity, but did not say when. Earlier in the afternoon, uniformed police officers were standing outside Wichita's city hall, which houses the police department. Police were also talking to the family of the person of interest.

Police in Wichita, the Sedgwick County District Attorney's office and the FBI all declined to comment to The Associated Press about the activity or any possible connection to the BTK case.

In December, the arrest of a Wichita resident on minor charges sparked widespread speculation of a possible link to the BTK serial killings. That man, who had no connection to the case, later filed a lawsuit alleging defamation against the media outlets that named him.

After taunting police with letters to news organizations throughout the 1970s, BTK disappeared before resurfacing a year ago, when he sent a letter to The Eagle claiming responsibility for an eighth killing in 1986.

In that letter, the killer included a copy of the victim's driver's license and photos of her slain body.

Police said they have received more than 5,000 tips from the public since BTK resurfaced.

FOX News' Carol McKinley and Rita Cosby and The Associated Press contributed to this report.