Inside the taunting Zodiac letter that made a reporter a target

The envelopes arrived at the San Francisco Chronicle with return addresses that did not exist.

Inside were letters, each one a taunt, each one carrying a cryptogram the killer dared the city to solve.

San Francisco Chronicle reporter Paul Avery opened them, read them, and wrote about them for his paper.

He wrote about the attacks in Vallejo, at Lake Berryessa, in the Presidio Heights neighborhood.

He wrote about the details the letters contained, details that only police knew.

The killer noticed.

Paul Avery became a target of the killer's threats.

The letters made him a target because he had done his job, because he had printed the taunts, because the killer wanted an audience and Avery gave him one.

The first cipher was solved by a Salinas high school teacher and his wife, Donald and Bettye Harden.

It read: "I like killing people because it is so much fun."

The solution was printed in the papers.

The public read it, and the unease spread through the Bay Area.

The letters confirmed the killer's involvement because they contained crime-scene facts that had not been released.

Not because the police had confirmed the author.

But because only the killer and the investigators could have known those details.

Was Avery a target because he was a reporter, or because he was the one who kept the story alive?

That would require evidence.

The case was never solved.

No suspect was ever charged.

The killer's identity is not established.

The letters proved a killer wrote them, but they never proved who the killer was.

THE FIRST ATTACKS

It began on a secluded road in Benicia, on December 20, 1968.

Two teenagers were shot there, parked on a lover’s lane.

A .22-caliber pistol was used.

The newspapers covered it as a local tragedy, a double homicide without a name attached.

Then came July 4, 1969, in Vallejo.

Two people were shot in a parked car; one died, the other survived.

The weapon was a 9mm Luger.

The surviving victim told police a man had approached the car, fired, and walked away.

By late September, the attacks crossed into a different kind of horror.

At Lake Berryessa, two people were stabbed; one died, the other survived.

The weapon was a knife.

Witnesses described a man in a hooded costume, an executioner’s mask.

Then, on October 11, 1969, a taxi driver was shot and killed in San Francisco’s Presidio Heights.

The weapon was a .38-caliber pistol.

Between December 1968 and October 1969, the killer later known as the Zodiac murdered at least five people across the Bay Area.

The geography widened. The violence escalated. The public read each new headline with a colder dread.

Police in Benicia, Vallejo, Napa County, and San Francisco each worked their own cases.

Coordination was poor.