Unsolved: As Team Name Zodiac Killer, How Many Other Serial Killers Remain Unidentified?

An investigative team led by retired FBI agents claims to have determined the identity of the mysterious Zodiac Killer.

The team said it was sure Gary Poste - who died in 2018 - was the killer but it was being prevented from running DNA tests for further confirmation.

From 1968 to 1969 a string of five murders in the San Francisco area were attributed to the "Zodiac Killer." The first three confirmed killings were attacks on couples, with the male partner surviving the later two encounters. The final, and fifth, confirmed "Zodiac" killing was of a San Francisco cab driver. However, the "Zodiac Killer" claims to have murdered 37 victims.

But even if the Zodiac Killer is conclusively identified once and for all, how many other serial killers are there out there who remain unidentified?

Obviously the most famous of them all, the “daddy” of all serial killers, is Jack The Ripper himself.

In 1888 a killer preyed on street prostitutes in the Whitechapel district of east London, often carrying out horrific mutilations which earned him the Fleet Street moniker.

The killings ended suddenly and nobody has ever been charged with any of them, let alone convicted.

Conspiracy theories abound and among those fingered as the killer are Aaron Kosminski, a Polish barber, artist Walter Sickert and even Prince Albert Victor, Duke of Clarence.

The bodies of 11 prostitutes were dumped in Long Island, New York between January 2011 and February 2012.

All of them had advertised their services on Craigslist and some had gone missing as early as 2003.

The victims included Shannan Gilbert, 24, from Jersey City, Maureen Brainard-Barnes, 25, from Norwich, Connecticut, Megan Waterman, 25, from Portland, Maine and Amber Costello, 27, from North Babylon, New York.

Among the chief suspects are John Bittrolff, who was convicted in 2017 of killing three prostitutes in 1993, long before Craigslist existed.

Confusingly there was another Craigslist Killer - Philip Markoff tied up and robbed sex workers he found on the listings website but committed suicide in August 2010, so the serial killer is sometimes referred to as the Craigslist Ripper.

Eight women - all sex workers - were murdered in the Hammersmith and Acton area of west London between 1959 and 1965.

The killer was dubbed Jack The Stripper by the press because the bodies were left naked.

But the killings stopped suddenly and the culprit - who no doubt also bore a hatred of women - was never brought to justice.

Kenneth Archibald, admitted killing one of the victims, Irene Lockwood, but he retracted his confession at trial and was acquitted because there was no evidence linking him to that murder or any of the others.

Among other suspects are former world champion boxer Freddie Mills, who committed suicide under suspicious circumstances in July 1965, and Harold Jones, a convicted murderer from Wales who was living in west London at the time.

Between 1968 and 1985 a serial killer attacked eight couples as they “made out” in cars parked in streets in and around the Italian city of Florence.

The killer was dubbed Il Mostro (The Monster) and the details of his crimes terrorised Italians.

He would shoot both victims and would often cut out the woman’s sexual organs.

Pietro Pacciani, a peasant farmer, was convicted of the murders in 1994 on the flimsiest of evidence and was freed on appeal two years later.

The prosecutor at his appeal, Piero Tony, said: “This investigation, if it weren’t so tragic, would put one in mind of the Pink Panther,” a reference to Peter Sellers’ bumbling detective.

Among the other suspects who have been put forward is Joe Bevilacqua, a former US Army soldier who is also accused of being the Zodiac Killer.

Antonio Banderas is to star as investigative journalist Mario Spezi in a TV mini series for StudioCanal about the Monster of Florence case.

Scotland’s most famous serial killer - Bible John - has never been caught.

Between February 1968 and October 1969 three young women vanished after meeting their killer at the famous Barrowlands ballroom and nightclub in Glasgow.

Their bodies were found in streets or alleys in the city a few days later. All had been beaten or strangled and one, Helen Puttock, had been raped.

All three were said to have been seen with a tall man with a Glaswegian accent who was overheard quoting from the Bible.

Nobody has ever been convicted of the murders.

In 1996 police exhumed the body of John McInnes - the cousin of one of the original suspects - and carried out DNA tests, which proved inconclusive.

Other suspects who have been put in the frame include Peter Tobin, who was jailed for life in 2006 for raping and murdering Angelika Kluk in the basement of a church in Glasgow. He had also killed two other women while living in England.

Between 2005 and 2009 the bodies of eight women - sex workers or drug addicts - were found in swamps in Jefferson Davis parish, Louisiana.

The first victim, Lynn Lewis, 28, was found floating in a river by a fisherman on 20 May 2005.

Other victims included Ernestine Marie Daniels Patterson, 30, Kristen Gary Lopez, 21, Whitnei Dubois, 26, Laconia “Muggy” Brown, 23, Crystal Shay Benoit Zeno, 24, and Brittney Gary, 17.

The final body - of Necole Guillory, 26 - was found off Interstate 10 in 2009.

The killings were the basis for the hit HBO TV series True Detective in 2014.

They have never been solved.

In the 1990s a series of prostitute murders in the English Midlands were reported to be the work of a single serial killer.

The victims included Gail Whitehouse and Janine Downes in Wolverhampton, Barbara Finn in Coventry, Carol Clarke in Gloucester and Lynne Trenholme in Chester.

In March 2000 Alun Kyte, a lorry driver from Stafford, was jailed for life for murdering two other Midlands prostitutes, Samo Paull and Tracey Turner.

Detectives later interviewed him in jail in connection with the other killings but have never confirmed there was a Midlands Ripper or that Kyte was a serial killer.