The Russian con artist who Scotland Yard thought was Jack the Ripper: Unseen police archive pictures show petty thief who was eventually ruled out as Victorian serial killer when it emerged he was in French prison at the time

A never-before-seen police file on Jack the Ripper has been found 136 years later by the great-grandson of a detective who worked on the case.

The fascinating archive includes two photographs of Michael Ostrog, an early suspect.

Ostrog, a Russian immigrant, was a petty thief and con artist who spent long periods in prison and in a mental asylum.

However, he was quickly ruled out as the Ripper as it emerged that he was in the lunatic wing of a French prison when the murders took place.

There is also the only copy in existence of the so-called Saucy Jack postcard the Ripper purportedly sent to the police to taunt them.

The original postcard is long-lost, making this facsimile copy the only one.

The archive also contains a copy of the 'Dear Boss' letter, a chilling note sent by the murderer to the police which he signed off as 'Jack the Ripper', the first time the name was referenced

A never-before-seen police file on Jack the Ripper has been found 136 years later by the great-grandson of a detective who worked on the case. The fascinating archive includes two photographs of Michael Ostrog (above), an early suspect for the Victorian serial killer

The archive also contains a copy of the 'Dear Boss' letter, a chilling note sent by the murderer to the police which he signed off as 'Jack the Ripper. The letter, which was dated September 25, 1888, was initially considered a hoax but police decided to take it seriously after the Ripper's fourth victim, Catherine Eddowes, was found with part of her right ear severed

The murderer boasted about killing his female victims and warned police that his knife was 'still nice and sharp'.

The original letter is held in the National Archives at Kew and there are only a few copies of it around.

And there is a grim photograph of the body of Ripper victim Mary Ann Nichols in the morgue.

The file was kept by Inspector Joseph Henry Helson who was serving in the Metropolitan Police when the infamous serial killer murdered five women in Whitechapel in 1888.

He worked on the murder of Nichols, an East End prostitute who was the Ripper's first victim.

She was found with her throat cut and mutilation wounds on her body in Buck's Row, Whitechapel, in the early hours of August 31, 1888.

The file was kept by Inspector Joseph Henry Helson (above) who was serving in the Metropolitan Police when the infamous serial killer murdered five women in Whitechapel in 1888 

He died aged 75 in 1920 and his collection, which includes his handcuffs, is being sold a century on

Inspector Helson took charge of the investigation and also assisted with enquiries into the killing of Annie Chapman, the Ripper's second victim, eight days later.

His archive has passed down four generations of the Helson family and is now being sold by a relative at Whitton & Laing Auctioneers of Exeter, Devon. It has an estimate of £10,000.

The auctioneers say that the previously-unknown collection should spark a bidding war as Ripper relics directly connected to his heinous crimes rarely come up for sale.

A Whitton & Laing spokesperson said: "For nearly 140 years the Jack the Ripper murders have held an enduring fascination and items directly connected to the crimes very rarely come up for sale.

"The items all belonged to Inspector Joseph Henry Helson and have been passed down through his family and are currently in the possession of his great grandson.

"Among the items to be sold are a mortuary photo of Mary Nichols which, although faded, seems to differ from the known photo with the camera at a very slightly different angle.

A photo card for early Jack the Ripper suspect Michael Ostrog

The collection of artefacts, which are being sold at Whitton & Laing Auctioneers of Exeter, Devon

"There are also two photos of one of the main suspects, Michael Ostrog, with notes to the reverse listing three of his aliases, criminal record and physical appearance.

"There is also a facsimile copy of both the infamous 'Dear Boss' letter and 'Saucy Jack' postcard which appears to be cut from the broadside printed in 1888 and used by the police in the hope that someone would recognise the handwriting.

"The original letter and postcard both disappeared, the letter being returned in 1988 and is now in the National Archives at Kew, but the postcard has never been seen again.

"This unique and important collection is to be offered as one lot and is expected to sell for in excess of £10,000.

"However people should not forget that the victims where real people with real stories and we wouldn't want to think of this murderer as a anti-hero but for the monstrous villain that he was."

Inspector Joseph Henry Helson (centre) and his team

Inspector Joseph Henry Helson's retirement stick. He died aged 75 in 1920

The 'Dear Boss' letter which was dated September 25, 1888, was initially considered a hoax but police decided to take it seriously after the Ripper's fourth victim, Catherine Eddowes, was found with part of her right ear severed.

The letter contained a promise to 'clip the lady's ears off'.

This prompted the police to publish numerous handbills containing duplicates of the letter and postcard signed 'Saucy Jack' in the hope someone would recognise the handwriting.

The original letter has apparent bloodstains on it.

Inspector Helson retired from the Met Police in 1895 after 26 years of service and returned to his native Devon to work on the railways.

He died aged 75 in 1920 and his collection, which includes his handcuffs, is being sold a century on.

The vendor, who recently inherited the items, would like them to go to someone who will appreciate them.

The sale takes place on March 22.

From hell: The infamous serial killer who terrorised Victorian London... but who was he (or she)?

One book named Queen Victoria's surgeon Sir John Williams (above), who had a surgery in Whitechapel at the time, as Jack the Ripper

Jack the Ripper is thought to have killed at least five young women in Whitechapel, East London, between August 31 and November 9, 1888, but was never caught.

Numerous individuals have been accused of being the serial killer.

At the time, police suspected the Ripper must have been a butcher, due to the way his victims were killed and the fact they were discovered near to the dockyards where meat was brought into the city.

There are several alleged links between the killer and royals. First is Sir William Gull, the royal physician. Many have accused him of helping get rid of the alleged prostitutes' bodies, while others claim he was the Ripper himself.

A book has named Queen Victoria's surgeon Sir John Williams as the infamous killer. He had a surgery in Whitechapel at the time.

Another theory links the murders with Queen Victoria's grandson, Prince Albert Victor, the Duke of Clarence.

At one point, cotton merchant James Maybrick was the number one suspect, following the publication of some of his diary which appeared to suggest he was the killer.

Some believe the diary to be a forgery, although no one has been able to suggest who forged it.

Other suspects include Montague John Druitt, a Dorset-born barrister. He killed himself in the Thames seven weeks after the last murder.

George Chapman, otherwise known as Severyn Kłosowski, is also a suspect after he poisoned three of his wives and was hanged in 1903.

Another suspected by police was Aaron Kosminski. He was admitted to Colney Hatch Lunatic Asylum and died there.

Dr Thomas Neill Cream poisoned four London prostitutes with strychnine and was hanged in 1892.

Some of the more bizarre theories about who the murderer was include author Lewis Carroll

Some of the more bizarre links include Lewis Carroll, author of the Alice In Wonderland books, who taught at Christ Church until 1881 - which was at the forefront of the Ripper murder scenery.

Winston Churchill's father - Lord Randolph Churchill - has also been named as a potential suspect.

Crime writer Patricia Cornwell believes she has 'cracked' the case by unearthing evidence that confirms the artist Walter Sickert was the prime suspect. Her theories have not been generally accepted.

Author William J Perring raised the possibility that Jack the Ripper might actually be 'Julia' - a Salvation Army soldier.

In The Seduction Of Mary Kelly, his novel about the life and times of the final victim, he suggests Jack the Ripper was in fact a woman.

In February 2019, it was suggested that Jack the Ripper may have been a sinister Dutch sailor who murdered two ex-wives in his homeland and bludgeoned to death two other women in Belgium.

Crime historian Dr Jan Bondeson has named Hendrik de Jong as a prime suspect for the most notorious set of unsolved murders in history.

At the time of the Whitechapel murders, de Jong is believed to have worked as a steward on a ship that made frequent trips from Rotterdam to London, providing him with the perfect means of getting out of the country after his heinous crimes.

He later murdered two of his ex-wives in his native Netherlands in 1893 and bludgeoned to death two women above a pub before attempting to set their bodies on fire in Belgium in 1898.

Police discovering the body of one of Jack the Ripper's victims, probably Catherine Eddowes