‘What sort of injuries to a victim would cause this kind of blood spatter on the defendant?’
‘The blood spatter is consistent with facial trauma – a violent assault to the face or nose, with the victim then blowing blood on to the attacker.’
Shocked murmurs rippled through the courtroom.
‘So Sebastian Croll was spattered with the victim’s expirated blood. Was there anything else about the blood on the defendant’s clothes which indicated that he had been involved in a violent incident with the deceased?’
‘In addition to the expirated blood found on the defendant’s T-shirt there was contact staining on the jeans and shoes, which suggested that the defendant had been in close proximity to the deceased at the time of the fatal assault. There was also a small amount of blood on the sole of the defendant’s shoe.’
‘What might the blood on the sole indicate?’
‘Well, this may have occurred as a result of standing in the victim’s blood, after the assault had taken place.’
‘Was there any forensic evidence which suggested that the violent incident had taken place where the body was discovered?’
‘Yes, the soiling on the knees of the defendant’s jeans and the bottom area of the victim’s trousers was consistent with the leaves and dirt found at the crime scene.’
‘Was any other biological material from the victim recovered from the defendant?’
‘Well, yes, the defendant’s skin was found under the victim’s fingernails and there were scratches on the defendant’s arms and neck.’
‘So Ben had tried to fight Sebastian off and scratched him in the process?’
‘That is how it appeared.’
Gordon Jones took his seat, as Irene Clarke rose.
‘Mr Watson,’ said Irene, not looking at the witness but instead consulting her notes, ‘when did you join the Home Office Forensic Science Service?’
Mr Watson straightened his tie then replied: ‘Just over thirty years ago.’
‘Thirty years. My! Quite a wealth of experience. You joined in 1979, is that correct?’
‘Yes.’
‘And in those thirty-one years of service, can you tell us how many cases you worked on?’
‘I have no way to tell without checking my records.’
‘Estimate for us – what would it be: thirty, a hundred, more than five hundred – how many, roughly?’
Irene was leaning forward on her lectern, shoulders near her ears. Daniel thought she looked like a girl leaning out of a window watching a parade.
‘In thirty-one years, I would say I have been directly involved in hundreds of cases, maybe less but maybe more than five hundred.’
‘And how many trials have you given evidence at in your thirty-one years of service?’
‘Over a hundred, I’m sure.’
‘Two hundred and seventy three, to be exact. You are indeed an expert witness. Tell me, in those two hundred and seventy-three cases, how many times have you given evidence for the defence?’
‘My evidence is impartial and I have no bias towards defence or prosecution.’
‘Of course. Let me clarify: in how many of your two hundred and seventy-three trials have you given evidence as a witness called by the prosecution?’
‘Most.’
‘Most. Would you hazard a guess at how many?’
‘Maybe two thirds?’
‘Not quite, Mr Watson. In two hundred and seventy three trials you have been cited as a witness for the defence only three times. Three times in thirty years. Do you find that surprising?’
‘A little, I would have expected a few more.’
‘I see. A few more. Regarding your qualifications, I see that you have a Bachelor of Arts from Nottingham … Economics. Do you find economics useful in your current field?’
‘I have since become a chartered biologist.’
‘I see. You have testified that there were fibres from Ben Stokes’s jeans on the defendant’s clothing. Tell me, would we not expect that two boys – neighbours – who played together might have fibres of each other’s clothes on their person as a result of normal play?’
‘It is possible, yes.’
‘Similarly, the defensive scratches on the defendant and the skin under the victim’s nails – these could have been the result of normal rough-and-tumble play between two schoolboys, could it not?’
‘It is possible.’
‘And you have also stated that the blood on Sebastian’s clothing was expirated. You testified that this was consistent with a blow to the nose or the face. Correct?’
‘Yes.’
‘The defendant made a statement to the effect that the victim fell and hit his nose while they were together, causing it to bleed severely. My client has stated that he leaned over the victim to inspect the injury. Tell us, is it possible that transfer of the identified expirated blood could have occurred under these more benign circumstances?’
‘The blood spatter is consistent with force, and I consider this to be the more likely cause, but it is possible that the expirated blood transfer could have been the result of the accidental injury you describe.’
‘One more thing,’ said Irene. ‘The blood on the defendant’s clothing – expirated, contact staining and otherwise – is minimal, would you say?’
‘There is a modest amount of blood on the clothes.’
‘The blood transfer was clearly evident on forensic examination – but referring to the photographs on page twenty-three of the bundle, it is not clearly apparent to the naked eye.’
Sebastian watched, eyes wide. Daniel remembered watching friends’ children viewing video games: their stillness unnatural in ones so young. Now Sebastian’s attention was also unnatural. He pored over the photographs of the blood spatter on the soiled clothing.
‘The blood spots were apparent to the naked eye, but they were not so large or significant as to be clearly identified as blood.’
‘I see. Thank you for that clarification, Mr Watson … With a severe injury of this type – blunt force trauma to the face – obviously carried out with the assailant in close proximity to the victim, would we not expect the attacker to be … covered in blood?’
Watson shifted in his seat. Daniel watched him. His ruddy facial colouring suggested that he was quick to anger.
The witness cleared his throat. ‘The type of injury would be consistent with significant loss of blood and we would expect significant transfer of blood on to the attacker.’
‘Typically, with this type of blunt force trauma, would you have expected the expirated blood and contact staining to be significantly more than the localised staining found on the defendant’s clothing?’
‘We have to remember the position of the body and the fact that most of the damage was done by internal bleeding … ’
‘I see,’ said Irene. ‘But you did just say that you would expect significant transfer of blood, nevertheless?’
Again Watson cleared his throat. He looked around the courtroom as if for help. Jones was staring at him, his chin pinched between two fingers.
‘Mr Watson, is it not the case that we would have expected the attacker’s clothes to be covered in blood with this type of injury?’
‘Typically, we would have expected a greater amount of contact staining, or airborne transfer of blood.’
‘Thank you, Mr Watson.’
The cross-examination had gone so well that Irene decided not to call the defence’s forensic scientist when the defence began. This turning of the Crown scientist to the defence’s benefit was more powerful.
The week closed with the Crown’s pathologist, Jill Gault. When she took the witness box, she was as warm and reassuring as she had seemed to Daniel in her office overlooking St James’s Park. She was tall, in boots and a grey suit. She looked like the kind of person who went rowing on weekends, untroubled by the knowledge of how – exactly – a child’s skull had been crushed.