WICHITA, Kan. – A man suspected in a string of 10 slayings that terrorized Wichita residents for more than three decades was being held yesterday on $10 million bond and could appear in court as early as today, prosecutors said.

At that appearance, Dennis Rader, 59, would stand in front of a judge on video while prosecutors recite yet-to-be filed criminal charges against him. The judge would also review Mr. Rader’s bond and set a permanent amount.

The hearing could happen today but was more likely to be postponed until tomorrow, the district attorney’s office said yesterday.

Late yesterday, an Associated Press report quoting an anonymous source said Mr. Rader had confessed to at least six of the BTK killings.

The source said investigators now believe Mr. Rader may have been responsible for as many 13 slayings. Mr. Rader made the confession on Friday, the same day as his arrest, according to the source. “The guy is telling us about the murders,” the source said.

Police spokeswoman Janet Johnson declined to comment.

Police were confident Mr. Rader’s arrest last week would bring to an end 30 years of fear about the BTK strangler. But as they pored over news of a suspect’s capture, many residents here were left with an unsettling feeling – that he had been hidden among them all along.

Mr. Rader, a married father of two, a Cub Scout leader, and an active member of a Lutheran church, was anything but a recluse.

His job as a city code enforcement supervisor required daily contact with the public, and he even appeared on television in 2001 in his tan city uniform for a story on vicious dogs running loose in Park City.

The Wichita Eagle reported that Mr. Rader also once worked at ADT home security company, where he held several positions that allowed him access to customers’ homes, including a role as installation manager.

He worked at ADT from 1974 to 1989, the same period as a majority of the killings.

At his church and around town, many expressed shock that Mr. Rader was accused of being the man responsible for at least 10 killings attributed to BTK – a self-coined nickname that stands for “Bind, Torture, Kill.”

“Disbelief, absolute disbelief,” said a tearful Carole Nelson, a member of Christ Lutheran Church, where Mr. Rader was an usher and the president of the church council. “I never would have guessed in a million years.”

The church’s pastor, Michael Clark, said Mr. Rader’s wife, Paula, was in a state of shock when he visited the family, who remained in seclusion yesterday.

“Her demeanor and voice indicated she was suffering,” Mr. Clark said.

Just days before his arrest, Mr. Rader brought spaghetti sauce and salad to a church supper, even though he was unable to attend himself, church member Paul Carlstedt said.

“The guy that walked in here was not the face of evil,” said Robert Smyser, an usher at the church.

Still, a sense of relief was palpable around Wichita after the apparent capture of the killer who had terrorized Wichita and sent taunting letters to the reporters since the 1970s.

“Hallelujah, praise the Lord,” Gaylene Brown said over breakfast yesterday at Don’s Restaurant, where Mr. Rader’s face was a common sight.

Mr. Rader was suspected of killing 10 people between 1974 and 1991. Law enforcement officials said they plan to turn the case over to prosecutors early this week. It was unclear whether Mr. Rader had a lawyer.

Police disclosed little about how they identified Mr. Rader as a suspect and have said they will not comment further on the case, but bits and pieces of the investigation have filtered out.

Kathleen Sebelius, governor of Kansas, told the Associated Press that DNA evidence was the key to cracking the case. It was unclear whether BTK’s letters helped lead to the arrest.

Police have said they obtained semen from the crime scenes even though the killer did not sexually assault his victims. Wichita television station KAKE, citing sources it did not name, reported that DNA from Mr. Rader’s daughter, Kerri, was instrumental in his capture, though KAKE anchor Larry Hatteberg said it did not appear the daughter turned in her father.

Charlie Otero, whose parents and two siblings were BTK’s first victims in 1974, said yesterday that he was “waiting with anticipation. I want to see the proof that the DNA matches.”

Mr. Otero believes his family was targeted, although the rest of BTK’s victims were likely chosen at random. He isn’t sure why the family was targeted but said it’s interesting that Mr. Rader and his father served in the Air Force at the same time in the 1960s. “I’m sure this will all come out during the trial,” he said.

District Attorney Nola Foulston said Saturday that her office could not pursue the death penalty against Mr. Rader because the 10 murders linked to BTK occurred before Kansas state law allowed capital punishment.

That didn’t sit well with some people – including Barbara Nottingham.

“I can’t believe we have that kind of system,” said Ms. Nottingham, 67, of Grand Lake, Okla. “I think if you committed a murder, you ought to be hanged.”

Parts of the profile released earlier by police seemed to match up. Investigators said they believed the killer was familiar with a professor at Wichita State University. Mr. Rader graduated from the university in 1979. In the 1970s, Mr. Rader worked at a nearby Coleman camping gear plant where two of his victims were employed.