New Zodiac Killer clue in the Sierra? Here's what drew one investigator to Hell Hole Reservoir.

An eerie rock formation in the Sierra Nevada that resembles the bull's-eye pattern used by the Zodiac Killer 

during his reign of terror in the Bay Area in the 1960s has been discovered, reigniting speculation about whether a key to the infamous killer's identity could be hidden in the Northern California mountains.

Despite global attention, the rocks have done nothing to ignite the curiosity of lifelong sleuths who have been following the murder case for decades,

some of whom had previously researched what turned out to be dead-end linkages to the Zodiac in the Sierra.

"We're not looking into it," Sgt. Nick Carlquist of the local South Lake Tahoe Police Department said simply, referring to the cold case of Donna Lass,

 who went missing from there in 1970 and is thought to have been slain by the Zodiac.

Mike Rodelli, whose 496-page book "In the Shadow of Mt. Diablo" is considered one of the most authoritative publications on the Zodiac case,

"It's difficult for me to believe that this was done by the Zodiac," he added. "It doesn't prove anything for a specific suspect."

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