Inside the envelope was a single sheet of paper on which had been photocopied a driving licence bearing the name Vicki Wegerle, whom Laviana recognised as the victim of an unsolved murder in the 1980s. Also on the sheet were copies of photographs that appeared to have been taken at a crime scene. He immediately contacted the police.
Though he had no idea at the time, the letter he had been handed was a direct link with the past - a traumatic past that most people in Wichita had long forgotten. But that past has now come back to torment this former cattle town in Kansas.
Days later, police told Laviana they believed the letter was from a serial killer who had terrorised the city during the 1970s. This man had called himself the BTK strangler. The initials stood for what he did to his victims - bind, torture and kill.
This same person was now also claiming responsibility for Wegerle's murder and the police believed him. Their evidence? Wegerle's driving licence had been missing since she was murdered and - before police arrived - emergency crews had removed her body from where she was found strangled. No crime scene photographs were ever taken - except, perhaps, by the person who had killed her.
Laviana received the letter last March. Since then BTK has sent a further seven messages to the police - the most recent just last week when a cereal box with the letters b, t and k circled, was left on a remote stretch of unpaved road north of the city. Several packages have apparently contained "mementoes" from his series of murders. Other information contained in the correspondence has also persuaded police they are genuine.
And yet for all these teasing, taunting communications, for all these glimpses of the murderer, it appears the police are no closer to catching him. More than 30 years after his first killings terrified the city, BTK remains at large. "My feelings about it are probably the same as everyone else's in Wichita," admits Laviana. "There is a morbid fascination [about BTK]. We all want to know who he is."
Wichita sits smack in the middle of the map - both geographically and culturally, it is at the heart of the American heartland. More than a century ago this city on the plains was known as a centre of the cattle trade. More recently it has been home to several major aircraft manufacturers such as Lear. Yet for all its development, for all the new museums that lie along the Arkansas river which cuts the city in two, on a fog-bound day in mid-winter when the freight trains clatter northwards along the frozen tracks, Wichita still feels like a place a long way from anywhere else. Its population of 350,000 might make it the biggest city in Kansas but one gets the sense that many of those people know one another: it is small-town America.
It was against this backdrop that BTK first struck on a snowy afternoon in January 1974. His victims were a family of four - the Oteros, who lived in a small, white-painted house in the east of the city. The family - Joseph and Julie and their two children - had been tied up and strangled. One of the children, 11-year-old Josephine, was left hanging from a pipe in the basement.
The killer sent a note "To whom?? Detail to come", bragging of his crimes and taking sole responsibility. "Those you have in custody are just talking to get publicity," he wrote. "I did it by myself and with no ones help."
In the next three years BTK killed three more women - Kathryn Bright, 21, Shirley Vian, 24, and 25-year-old Nancy Fox - cutting the phone lines to their homes before striking. In the last of these murders, the killer's voice was recorded when he dialled the emergency services to alert them to the crime. Though none of the victims was sexually assaulted, BTK also left DNA samples, reportedly semen, at some of the crime scenes.
But at the time none of these three killings or the murder of the Otero family had been linked by police. The revelation that Wichita was being preyed on by a serial killer did not come until February 1978 when BTK sent a letter to the local television station claiming responsibility for all seven killings. Police warned an anxious public that he might strike again.
And yet, as far as the police or anyone else in Wichita knew, BTK did not strike again. The killing of Vicki Wegerle in 1986 was not linked to the earlier killings and gradually people started to presume that BTK had either left the area or been jailed for another crime. Many thought - or at least hoped - he had died. The letter sent to The Wichita Eagle's offices last March forced people to think again.
The realisation that BTK is alive and still thinking about his crimes has gripped the people of Wichita. Though the sales of firearms and house alarms initially saw a boost, people appear to be not so much terrified - not, at least, as they were in the 1970s - as they are sickened and disturbed.
People realise this person must be living among them, blending in, watching them maybe. They believe he is playing with them, taunting police by leaving these partial clues and "trophies". It has led to all manner of theorising and conspiracies, not just among the people of Wichita but on internet chat boards dedicated to the topic. It has also generated a fair degree of suspicion and paranoia.
"He is a yellow-bellied snake of a coward of a creature," says Vern Miller, 81, who was the city's sheriff during the 1960s and attorney general of Kansas during the early 1970s. "It sure gives one pause for thought. Just three weeks ago I was speaking to a judge who said to me `I thought it was you'. Then I was in a tyre shop a few days later and a lady had told them Vern Miller was BTK. When I heard that, I went straight to the police and gave them a DNA sample."
At the house on North Edgemoor Street where the Oteros were killed, the current residents, Buffy Lietz and her family, became so fed-up with the media and ghoulish sight-seers they appealed through the local newspaper for privacy. Lietz, a Mormon, said it had become so bad she feared she would not be able to sell her home because she would be inundated by timewasters, who simply wanted to see where the killing took place. On the wall of her living room, Lietz has placed a sign that reads: "God Lives Here".
A neighbour, Joseph, who has lived two doors away for 20 years, says he cannot understand why the police have not had more success. "I think people are fed up that the police have not caught him. He has been leaving them clues," he says. "You watch all these things on TV about the police forensics experts and you just feel that they should get those people in."
What exactly is known about BTK? Last March, after the Eagle received the letter, police revealed these details about the killer based on the correspondence he had sent over the years. BTK claims he was born in 1939, that his father died in the Second World War, that his mother worked during the day near the railroad and that she dated a railroad detective when he was 11, that he attended Sunday school and that his first job was as a mechanic. From their inquiries police also believe BTK frequented the campus of Wichita State University during the 1970s and that he knew a now dead lecturer, PJ Wyatt, who taught there.
Since last March, the police have had very little to say in public about the case - believing they will be less likely to encourage hoaxers by limiting the information they reveal.
One of the things they have not commented on is what might be inspiring the ageing killer to start communicating again after all these years. Some people believe BTK has recently been released from jail and returned to Wichita, others suspect he may be dying and may even be trying to get caught. Others say he simply likes the publicity and the idea that he is out-witting the police.
Robert Beattie, 48, who lectures in political science at a local university, probably knows as much as anyone about BTK. He is just completing a book on the topic that is due to be published later this year.
He says he has heard all the theories about BTK's motivation and yet remains unsure. "I have been baffled," he admits. "I'm not a psychologist and those I have spoken to on the case do not all agree. The retired detectives I have spoken to seem to think that he wants some sort of attention. One detective said he believed BTK is the killer's real persona and that John Smith, or whoever, is his alter ego. He sees himself as this serial killer and only sometimes is he the other person. One psychologist said he hid behind a mask of sanity."
Other than indulging in this sort of speculation there is very little for the people of Wichita to do but wait and see if the police are able to identify BTK and finally bring this story to a close. Last December there was great excitement when police arrested a man, Roger Valadez, about whom they had received an anonymous tip. He was quickly released without charge after giving a DNA sample.
Who knows if the BTK case will ever be solved? One thing that seems clear is that BTK himself will only, or can only, go so far in helping the authorities. In what is believed to have been his first correspondence with the police and public - a letter he sent to The Wichita Eagle after the Otero murders in 1974 - he warned: "When this monster entered my brain, I will never know, but it is here to stay. How does one cure himself? I can't stop it, the monster goes on, and hurts me as well as society. Maybe you can stop him. I can't."Reuse content