I'm UK's top blood spatter expert…the goriest crime scene I've ever seen & how my grisly new evidence freed innocent man

The Sun

16-05-2025

It looked like an open and shut case - two 'killers' caught running away from a blood-soaked crime scene.
The victim was labourer Grzegorz Pietrycki, 25, who died from a slashed throat after jumping from a window at his flat, staggering 200ft down the road and ringing a stranger's doorbell, leaving a bloody trail in his wake.
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Suspicion fell on two friends he had spent the weekend partying with at his home in Wood Green, London in August 2016.
When they were caught on CCTV footage running away from the property, it looked like they were bang to rights.
One of the pals, Patryk Pacheka, 30, was convicted of murder at the Old Bailey a year after the savage killing.
But Patryk's barrister was convinced of his innocence and contacted Inside Justice, a charity which campaigns on wrongful convictions.
They called in one of Britain's top blood spatter analysts, Jo Millington - consultant to TV show Silent Witness - and what she discovered was mind-blowing.
Jo, who has worked on cases like the 7/7 terror attacks, said cops concentrated on the carnage at Grzegorz's flat but failed to examine the pattern of blood that led to the wall where he finally collapsed.
She told The Sun: 'On the path between the victim's flat and the place where he collapsed there was a trail of blood which hadn't been examined.
'It showed a spot behind a parked car where the blood staining became more persistent and ferocious, and indicated that the deceased had probably sustained his fatal injury there.'
The blood spatters revealed that, while Grzegorz was attacked in his flat, the stains on the pavement showed that was where his throat had been slit.
Doorbell cameras later revealed that, far from running away from a murder, Patryk and his friend were running away from a third man. It was he who'd allegedly carried out both attacks on Grzegorz.
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Jo said: 'Patryk and his friend had no part to play in that attack. He was convicted because the assumption was made that the bedroom was the place where the fatal injury took place, and Patryk had access to the flat.'
Patryk was released after a re-trial which found him not guilty in 2021, and went back home to his family in Dansk in Poland.
He said at the time: 'Now I am free. This is amazing. I cannot describe what I feel right now. I owe everyone.
'Ten days ago I was in prison and now I am in my house with my family. I am the happiest man in the world.'
Childhood dream
Jo, 52, of Reading, is one of the country's leading forensic specialists with almost three decades of experience.
She trained in Miami with the world's eminent blood spatter expert Toby Wolson, who advises on the TV show Dexter.
The long-running series focuses on a police forensic officer with a dark secret as a serial killer who murders killers who escaped justice.
Jo dreamed of working in the field after watching 1980s drama Indelible Evidence, in which actors recreated the work of forensics teams to solve crime.
She said: 'My mum and I used to watch it together and I just knew it was what I wanted to do.
'At the time schools didn't like you to specialise too much when you chose your options at high school, so my parents had to ask for special dispensation so I could drop the humanities like geography and history, and concentrate on the three sciences instead.'
Peanut clue
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It was a move that brought Jo into a world of darkness, attending grisly murder scenes and analysing evidence.
She even helped identify the terrorists who killed 52 people in the July 7 London attacks in 2005.
Jo was asked to examine a car used by three of the four bombers who travelled from Yorkshire to Luton airport in a hired Nissan Micra.
The car had already been blown up in a controlled explosion, amid fears it was booby-trapped, and Jo recalls having to wriggle through the smashed driver and passenger windows to find evidence.
She spotted an empty packet of KP peanuts in a side pocket and deduced it had been torn open with teeth.
'The car had been wrecked and the central locking system wasn't working so we couldn't open the doors, but the front windows were out,' says Jo.
'I was looking for hairs, fibres or any material that might have been left in the car. We swab things that people would naturally touch while driving, like the gear stick, the indicator stalk and the steering wheel.
'I put a little bit of material, sort of like wool, on the driver side window so I wouldn't cut myself and leaned in.
'When I looked down at the pocket of the driver's door there was a little empty KP peanut packet and the corner had been ripped open. It was kind of creased and funny looking, as though somebody had used their teeth.'
It allowed cops to identify Shehzad Tanweer, 22, who killed seven innocents at Aldgate on the Circle Line of the London Underground.
He was the righthand man of ringleader Mohammad Khan, 30, who murdered six with a bomb at Edgware Road.
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'His face was barely recognisable'
Jo says many murder scenes she visits still have the victim in-situ, but after years as an analyst, she is now able to detach herself from the emotion of cases to do her job.
One particularly gruesome murder in Sussex still shocked her, though.
When staff at an architects office went into work one day they saw blood dripping down the walls from a flat upstairs.
Jo said: 'They called the police who went into the flat and found a man with machete injuries so bad that his face was barely recognisable and the injuries were very severe.
'There was a lot of blood but when you walked about from the deceased, there was a trail of drops that led around the flat.
'In areas where you might stop and look in a drawer or open a cupboard there were even more drops.
They called the police who went into the flat and found a man with machete injuries so bad that his face was barely recognisable and the injuries were very severe
Jo Millington
'To my mind, that said there was someone else at the scene who was injured.
"They were dripping blood, which was sparse until they stopped to maybe look for valuables, and the blood started to drip more consistently.
'That blood was swabbed for DNA and someone was ultimately found guilty of the killing.'
Secrets of Silent Witness
By Grace Macaskill
Jo is a forensics advisor to hit BBC show Silent Witness and often recreates bloody crime scenes for the programme.
She says the standard of accuracy on the series is 'really high' as producers battle to make it as realistic as possible.
She reveals that mushed up mango and other fruit is used for brain matter while there are different types of 'blood' for different injuries.
Jo told The Sun: 'The appetite to get everything absolutely right is really, really high. They want to be as authentic as possible.
'In the last season there was a scene where somebody had a gunshot injury to his head.
'An exit wound creates blood and brain, material and bone, and I used mushed up mango for the brain matter. Mashed up fruit gives that 3D look.
'The make-up department is just off the charts in terms of the way they work. There's a wardrobe of different blood types; clotted, liquid and pre-made silicone pools.
'The silicone is used when a lot of shots need to be taken and if liquid blood was used, it would change with each take.'
Jo said stars Emilia Fox and David Caves are now getting the inside track on forensics.
She said: 'Sometimes they'll ask, 'How do we do this', and you'll be like, 'You've already done it.' They've been doing the roles for so long that they can now do tests in an almost identical way to the real forensics teams.'
Bearing witness to some of the most horrific crimes in the country has given Jo a special perspective on life.
She said: 'The longer you do the job and the older you get, you start to become more reflective on your experiences.
'I think what my job has done is put things into perspective. If something trivial happens and someone is getting stressed, I'm often the one saying, 'Look, this is small fry, don't worry about it.'
'Life is so finite and people do horrible things to each other, unfortunately, but I have a lovely home life that compensates.'
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