The letters and poems began arriving in 1974. Shot through with spelling and grammatical errors, they alternated between tortured rambling and cold-blooded, gleeful detail.

Then, the BTK killer (search) — since linked to eight unsolved killings between 1974 and 1986 — vanished. But he resurfaced last March with new letters to police and media and, although still enigmatic, they have taken a new tone.

The frequency of the new communications and the accompanying attention concern at least one researcher.

"For some of these killers, there is kind of a cycle that once the spiral begins to accelerate the next step is to kill and get a whole new generation of people scared," said Dirk Gibson, author of "Clues from Killers: Serial Murder and Crime Scene Messages."

The killer once raved about his inability to control a "monster" living inside him and gave graphic descriptions of his crimes. The few details released about the new messages indicate a businesslike, almost cordial approach.

Officials said last week the killer had recently sent at least three packages containing jewelry, and investigators were trying to determine whether any of it was taken from BTK's victims.

Along with a padded manila envelope sent to KSAS-TV in Wichita, the communications included a cereal box found in a rural area northwest of Wichita in late January and a package found a few days later that police identified only as Communication No. 7.

Gibson, who has studied more than 500 serial killers (search), said BTK loves the attention. That was already apparent in the 1970s, when the self-named BTK — the initials stand for "Bind, Torture, Kill — terrorized Wichita.

When one of his messages, a poem sent to the Wichita Eagle-Beacon on Jan. 31, 1978, was mistakenly routed to the classified ads department, BTK sent a letter to KAKE-TV days later complaining: "How many do I have to kill before I get my name in the paper or some national attention?"

Another letter to the newspaper also underscored BTK's need for recognition.

"P.S. How about some name for me, its time: 7 down and many more to go," it read in part. "I like the following. How about you? 'THE B.T.K STRANGLER, 'WICHITA STRANGLER', 'POETIC STRANGLER', 'THE BONDAGE STRANGER' OR 'PSYCHO', 'THE WICHITA HANGMAN', 'THE WICHITA EXECUTIONER,' 'THE GAROTE PHATHOM', 'THE ASPHYXIATER'."

KAKE-TV has also received communiqués from BTK since his re-emergence, some of which contain messages for police.

But the tenor has changed: In a postcard sent earlier this month, BTK thanked the station for its quick response to two other messages and expressed concern for two news anchors after a passing comment one made on the air about having the flu.

Randy Brown, a senior fellow at Wichita State University's Elliott School of Journalism, was a reporter at the now-defunct Wichita Sun when the weekly paper first broke the story about BTK in the 1970s.

"This is a very different BTK than the original," Brown said. "The first letters were full of horrifying details of these crimes, ravings and very graphic information about the victims and the monster in his brain — ugly, nasty, scary, terrible kinds of things that people who saw them still have bad dreams about."

Although no recent deaths have been officially linked to BTK since he resurfaced last year, the case has received worldwide attention.

"It is hard to believe this is really the same twisted killer that was scaring the heck out of everybody — had a town completely on edge — in the late 1970s and 1980s," Brown said.