MYSTERY WIRE (SAN FRANCISCO – KRON) – Could there soon be new details released in the Zodiac case?

The FBI San Francisco Division on Friday announced it is aware and investigating after a cipher attributed to the Zodiac Killer was recently solved by private citizens.

“The Zodiac Killer terrorized communities across Northern California and even though decades have gone by, we continue to seek justice for the victims of these brutal crimes,” the FBI tweeted in a statement. “Due to the ongoing nature of the investigation and out of respect for the victims and their families, we will not be providing further comment at this time.”

Police say at least five people are believed to have been murdered by the Zodiac, although the killer claimed at least 37 victims since 1966 in his letters.

The Zodiac would write notes, often threatening to kill, in a cryptogram composed of bizarre series of letters and symbols.

The killer, who has never been identified, signed the letters with a circle divided by a cross. Subsequent letters began, ″This is the Zodiac speaking.″

His last authenticated letter to the San Francisco Chronicle arrived Jan. 30, 1974.

The Associated Press contributed to this report.