WICHITA, Kan. - More than two decades have passed since a serial killer terrorized Wichita, strangling or stabbing seven victims and bragging about it to the media. Police hadn't heard a peep from the killer in 25 years — until now. On March 19, a letter arrived at The Wichita Eagle with information on an unsolved 1986 killing, a copy of the victim's driver's license and photos of her slain body. The letter, apparently from the killer known as the BTK Strangler, sparked increased demand around Wichita for home security systems. But it also rekindled hope that modern forensic science can find some clue that finally will lead police to a killer most thought was dead or safely locked in prison for some other crime. "I don't know why he does all of this, but I hope this will be his fatal mistake by resurfacing this way," Dale Fox, whose daughter Nancy was bound and strangled in December 1977, told The Associated Press. The letter sent to the Eagle was the first clue that the 1986 killing of Vicki Wegerle might have been at the hands of BTK, an acronym the killer used for "bind, torture and kill." Six of BTK's victims were strangled; one was stabbed to death. Four were members of one family — two children and their parents. Letters claiming responsibility for the slayings were sent to The Wichita Eagle and KAKE-TV. The serial killer's first letter was found in a textbook at the public library; he went on to send poems and called police with details of Nancy Fox's slaying. In one letter, he taunted: "How about some name for me, it's time: 7 down and many more to go." Detectives are looking through lists of inmates who have recently been released, in case the reason they had not heard from the BTK Strangler since 1979 is that he was in prison. The latest missive arrived at the Eagle on March 19. It contained a single sheet of paper with a photocopy of Wegerle's driver's license and three pictures, each showing the victim in a slightly different pose. Relatives said the license was the only thing they know of that was missing from her home. Police said they had no crime scene photographs of Wegerle's body because it was removed by emergency medical service workers before officers arrived. Word about the letter leaked Wednesday night, and police confirmed Thursday they had linked it to BTK. Police will not say why they are convinced it came from BTK and the Eagle said it agreed not to publish several of the details in the letter that led police to the conclusion. By Friday, police had received 365 tips through an anonymous phone line and e-mail address, said Lt. Ken Landwehr, who has worked the case for than 20 years. At the same time, the number of calls to SecureNet Alarm Systems have increased almost ninefold since the new letter surfaced, public relations director Chuck Hadsell said. Thousands of home security systems were installed in Wichita in the 1970s because of the BTK killings, and some of those customers want to update their systems, Hadsell said. For one thing, today's systems are triggered if phone lines are cut, a trademark of the BTK killings in the '70s. The news struck so hard for Dale Fox that he broke down Thursday when film of his daughter's home was shown on television during a news report about BTK. His daughter's body was so bruised when he went to identify it that it was hard to recognize her. "It was such a brutal murder," said Ruth Fox, Nancy Fox's stepmother. "To brutally murder someone like BTK has done to his victims, I have no mercy for him at all." At first, the letter that arrived at The Eagle generated little interest. "We get letters like this all the time, letters that are not news," said police reporter Hurst Laviana, who was assigned to check it out. Laviana recognized Vicki Wegerle's name. "I kept thinking this isn't the typical crack letter," he said. Police Capt. Darrell Haynes told him the letter was probably nothing, and he didn't give it to homicide detectives until Laviana reminded him three days later. On Wednesday, police told Laviana the letter was authentic. It is being processed for fingerprints and DNA evidence, and evidence from the Wegerle homicide is being reprocessed using technology not available in 1986. The return address on the letter said it was from Bill Thomas Killman — initials BTK. The address appeared to refer to a now-vacant building. The letter was mailed in Wichita, Landwehr said Thursday. He said it contained no suggestion that the killer planned to strike again. Wegerle's sister-in-law, Norma Wegerle, said the family often wondered whether BTK could have been involved in the killing. "We just want it to be solved so we can get closure," she said. "There's hopefulness that somebody might actually be found. We want it to be solved."