The computer that is attempting to decode the cryptic letters signed by the Zodiac killer can also produce haunting poems.

The Zodiac killings are a series of unsolved murders that took place from December 1968 to the early 1970s in Northern California.

The identity of the killer, allegedly responsible for the deaths of at least five people, and the targeting of a further two, remains unknown.

In addition to being a famously unsolved murder, the Zodiac gained public attention because of the letters detailing the crimes, written in code, that were frequently sent to newspapers.

The name 'Zodiac' came from one of the symbols used in the letter, and by the description given by one of the survivors of an attempted murder

Officially declared to be 'inactive' in 2004, the case remains the subject of enthusiastic amateur investigations.

CARMEL the code breaker/poet computer

One such investigation has set an artificial intelligence on the case to decode some of the Zodiac letters.

In the early days, the Zodiac killer's first messages were decoded by human crossword enthusiasts.

Now, CARMEL the codebreaking machine based at the University of California's Information Science Institute is now taking on the heavy burden.

It has an online tool, and bizarrely, it can be used to create haunting poems, based on words from the decoded letters.

When indy100 asked the tool to write about 'love', with four lines, in the form of a Shakespearean sonnet, it wrote:

Forget about the kiss of Juliet, Such an old romantic comedy, I wanna know a little love duet, The likes of you and me and everybody.

In case this was just a creepy coincidence, because a love poem written by the Zodiac killer was always going to be weird, indy100 used a random word generator to select the subject matter.

'Active' created these four lines:

A number one political career! Or ever thought about the leading figure, The ways of living on a volunteer, Like an occupation actor singer.

Still creepy.

'Freight'

About a hundred million dollar mail! Or lots of trouble on Milwaukee road, Tons of water from an old ho scale, A smash between the eyes and then unload.

CARMEL'S moonlighting as a poet was revealed on a new documentary for the History channel, entitled Zodiac Killer: Case Closed?

The five part programme airs Wednesday at 9pm on History UK, and repeats on Fridays at 10pm.

The first episode aired on 22 November, and detailed the activities of CARMEL.

According to History the creator of CARMEL is professor Kevin Knight, an expert in natural language processing.

Previously CARMEL was used to unlock the Copiale Cipher, a handwritten 105 page manuscript written in code from the 18th century, which was used by a secret German club.

If you don't plan on sleeping ever again, take a listen to the audio versions of some of the other poems created by CARMEL from Zodiac ciphers.