Lined up in a cell in Norwich Castle Museum's dungeon, their lifeless faces may look eerily calm, but these 'death heads' were thought to hold the secret to identifying psychopaths. Weird Norfolk goes underground to discover the hidden history of Norfolk's murderers.

Eastern Daily Press: The death masks at Norwich Castle. PICTURE: Jamie HoneywoodThe death masks at Norwich Castle. PICTURE: Jamie Honeywood (Image: Jamie HoneywoodArchantNorwichNorfolk)

Deep beneath the castle, where people were held in darkness for months, chained to the walls and tortured, it is easy to believe that something of the unspeakable horror of the past might live on in these chalk-white faces.

It's difficult not to feel the presence of the dead as you stare into the faces of murderers, a line-up of executed villainry frozen in time, warts and all, a snapshot of the soul.

Death masks had to be made quickly, within a matter of hours after someone had breathed their last: this meant that features weren't ruined by bloating and would be as accurate as possible, down to the last detail, such as the jagged edge of an executioner's axe.

Painters and sculptors would use masks as references from which they could create art and before the invention of photography, the police would use the masks to record the features of unidentified bodies in the hope they would be recognised by people desperate to find a loved one.

Eastern Daily Press: The death masks at Norwich Castle. PICTURE: Jamie HoneywoodThe death masks at Norwich Castle. PICTURE: Jamie Honeywood (Image: Jamie HoneywoodArchantNorwichNorfolk)

In the 19th and early 20th century, the process of making death masks began to take a more sinister turn: executed prisoners began to have their faces preserved for posterity, their heads shaved and a cast taken for a curious new discipline known as phrenology.

Developed in 1796 by German physician Franz Josepf Gall, the process involved in phrenology involves feeling and observing the measurements of a human skull with the theory being that certain behaviours and traits are confined to different sections of the brain.

By 'feeling the bumps', a phrenologist claimed to be able to assess character and temperament: and by collecting death masks or heads of famous people and criminals, it was believed that patterns could be established which could identify potential in people before it happened.

The art fell in and out of favour although by the time that Norwich's most famous death mask maker was in business, interest was gathering in the study of murderers and whether or not you could identify a dangerous criminal simply by the bumps on their skull.

Eastern Daily Press: A look at the way Norwich was in the “tough” old days. Photos: Archant library.A look at the way Norwich was in the “tough” old days. Photos: Archant library. (Image: Archant)

Giovanni Bianchi was born in the Lucca area of Tuscany. He arrived in London in the summer of 1836 and met and married Sarah Rivett, from Ipswich St Margaret – she was 19 to his 28 - a year later, their first child Alessandro born a month later. Little Alessandro died aged just 10 months.

A maker of busts, Giovanni and Sarah had two other children, Giovanni and Mary Ann, who were born and baptised in Great Yarmouth and by 1841, the family had moved to Norwich and were living in Colegate where a further six children were born.

Giovanni Senior stepped into the shoes of plaster figure maker Pellegrino Mazzotti and, between 1837 and 1854 Bianchi made death masks of various notorious criminals including James Greenacre, Daniel Good, Samuel Yarham, James Bloomfield Rush, Henry Groom and William Thompson, all in the collection of Norwich Castle Museum. The first two were executed at Newgate Prison in London, but the others at Norwich Castle.

Death masks have been made for centuries, the most famous being the mask of Tutankhamun and the Romans ritually kept death masks of their ancestors for display and worship. By the 19th century and Bianchi's time, they were not only used for scientific study, but as a deterrent to would-be criminals.

Eastern Daily Press: Norwich Castle keep exterior.Norwich Castle keep exterior. (Image: Archant)

Before photography was readily available, the death mask served as a terrifyingly accurate portrayal of a person, capturing a resemblance that cannot be denied – and their final expression, whether it be a look of peace or distress, a smirk or a lack of remorse. In many cases you can see wounds in the cast, a contortion in the neck where a body was hanged, a jagged cut where a head was severed from its body.

James Greenacre, 52, was hanged at Newgate Prison on May 2 1837 for the murder and later dissection of Hannah Brown, his fiancé. His death head is in Norwich Castle's dungeon close to that of Daniel Good, whose murder of an unknown person and constant police evasion led to the setting up of the Detective Branch in London. Both heads are the work of Bianchi.

Samuel Yarham, hanged at Norwich Castle on 11 April 1846 for the murder of Harriet Candler was cast by Bianchi hours after his death: 'A cast was afterwards taken of his head and face, by Bianchi, of St George's, and this latter exhibits a placid expression, the very reverse which might have been expected from his crime,' said the Norwich Mercury of April 18 1846.

James Blomefield Rush, 49, hanged at Norwich Castle on 21 April 1849 after a heinous crime which saw him, on a winter evening in 1848 at Stanfield Hall near Wymondham, he blew the heart out of the recorder of Norwich, Isaac Jermy, he murdered Jermy's son, shot the arm off the son's wife and grievously wounded an unfortunate servant girl.

'After hanging the due time, the body was cut down, and in the course of the afternoon the head was shaven and a cast taken of the features and skull by Bianchi of St George's Middle street in this city. The remains were then buried, according to sentence, in the precincts of the prison,' noted the Norwich Mercury at the time.

Sir Robert Bignold later wrote: 'The clerks of the Norwich Union took the morning off, which was quite in accordance with precedent on execution days, and no doubt Bianchi the Modeller did a good trade. It is even probable that some of the Norwich Union clerks were among his customers, for we have it on the authority of the chief clerk that it was not unusual for the staff to buy the casts of murderers in those days and hide them in their office desks.'

Joining the ghastly line-up is Henry Groom, 42, hanged at Norwich Castle on 16 August 1851 for the murder of John Ayton, William Thompson, 21, hanged at Norwich Castle in 1854 for the murder of Lorenz Beha. Two other masks, those of the Burnham Poisoners Catherine Frarery and Frances Billing, can also be seen in Norwich Castle Museum.

• Dungeon tours are only available with the purchase of a general admission ticket to Norwich Castle and cost an additional £4.50 per person, per tour. All tours are subject to availability and are booked on the day. If you are planning to make a special trip for a tour, contact the Castle on 01603 495897/ 493625 on the morning of your visit to check availability. Dungeon tours are not suitable for young children under the age of five. Due to uneven floors and stair access they are also unsuitable for people with mobility difficulties.