Message #143640

[Copperhead]

In a further unique twist, Ms Perez even said she had helped her father scribble some of the killer's infamous confession notes, in which he taunted police, newspapers and amateur sleuths with elaborate ciphers and riddles, claiming responsibility for 37 deaths.

"I was a child and just thought I was helping my dad," claimed Ms Perez, 47, one of six children adopted by Hendrickson, who died in the 1980s. "I didn't know. He told me he was sick, and all I wanted to do was help my dad ... He kept telling me he was sick and he killed many, many people. I had no idea."

She was speaking at a surreal press conference outside the offices of the San Francisco Chronicle, one of the newspapers that received several of the letters, on Wednesday afternoon. It was attended by journalists and Zodiac enthusiasts holding photos of suspects.

Local police, who have never closed their investigation, said: "We get a significant number of calls a year," said Sergeant Lyn Tomioka. "We look into whatever evidence is presented to us."

The development will open yet another chapter in a case which has fascinated Hollywood for decades, providing the loose inspiration for the Clint Eastwood hit Dirty Harry and the hit 2007 thriller Zodiac, among others.