Wichita ? As a former census supervisor in 1989, serial killer Dennis Rader traveled Kansas trolling for victims – even digging a grave for one potential victim in northern Kansas. As Park City’s ordinance enforcement officer, he stalked neighborhoods closer to home until his arrest.

Rader was planning to kill again. Wichita Police Chief Norman Williams said Friday he even had set a date: Oct. 22, 2004.

Police declined to identify the potential victim, who lives near Wichita.

“The fact that he was communicating, the fact that he was still active. He was a threat to this community,” Williams said.

While this week’s sentencing answered decades-old questions for the community, it also left lingering questions of whether there are other unsolved murders here or around the state – perhaps committed after the death penalty was enacted – to which Rader never confessed.

Friday, the state’s top law enforcement officials working on the BTK task force said they could only account for 10 murders, although they had evidence Rader was involved in other burglaries.

But they also acknowledged they never linked Rader to two Park City murders until he confessed to them after his capture. None of the evidence collected points to him in other unsolved cold cases, they said.

FBI special agent Kevin Stafford said investigators believed a person with his personality type would have told police about additional murders. Kansas Bureau of Investigation director Larry Welch said that during Rader’s interrogations, interviewers “couldn’t shut him up.”

“If there are any additional, he would have told us,” Williams said.

As he was driven to the El Dorado prison Friday, Rader, 60, talked about the weather, commenting how green the scenery was and how good the countryside looked, Sedgwick County Sheriff Gary Steed said.

“It was somewhat surreal in that while we were driving over we were listening to one of the radio stations. … They were playing victim family statements over the radio and he was listening to it,” Steed said. “During that time he stared out the window, and when he turned and looked at me, he had tears in his eyes.”

Rader told law enforcement officials as they were arriving at El Dorado that he hoped someday his incarceration would contribute in some way to preventing future serial killings, Steed said.

Police got their big break in the 31-year-old BTK case in a flurry of communications that came in the months before Rader’s arrest.

In one, Rader asked police: “Can I communicate with Floppy (sic) and not be traced to a computer. Be honest.” BTK told police to respond by running an ad in the newspaper’s classified section, under miscellaneous, saying, “Rex, it will be OK.”

Investigators ran the classified ad on Jan. 30, police case documents show.

On Feb. 16, Rader sent his 11th and final communication: a package mailed to KSAS-TV containing a floppy diskette. Police determined it came from Christ Lutheran Church. On it, investigators also found the name “Dennis.” A Google search showed that Dennis Rader was president of the congregation at that church.

Their suspicions were confirmed when DNA from three of the crime scenes was a familial match to a DNA sample from Rader’s daughter, police said.

“His arrogance helped catch him. … He should have kept his mouth shut,” Welch said.

During his sentencing, Rader told the court that the only sore spot he felt in the investigation of the killings was the use of his daughter’s DNA.

Welch said he wanted Rader to know that he was proud of obtaining that DNA: “I’m glad we contributed to his ‘sore spot.”‘

During his nearly six-month stay at the Sedgwick County jail while awaiting trial, Rader received 436 letters, with another 34 items of mail returned because of contraband such as cash or stamps. He also got 66 media requests. Steed said he would not characterize any of the letters as fan mail.

Rader sent out more than 300 letters to 43 cities in 12 states and Holland.

Williams told reporters Friday: “Bottom line: BTK is history.”