‘You said you want to know two things as a priority, sir — if I can pinpoint the approximate location of the shooter, and establish what the weapon was?’
Grace nodded. ‘I want to get search officers looking for evidence around the scene of where the shooter was located. He might well have spent some time in his location.’
‘If he’s a professional, almost certainly he’d have been there a while. But if he’s a pro — a sniper very likely — he’ll also know how to cover his tracks pretty efficiently.’ He looked up and, squinting against the sun, surveyed the landscape. Then he traced an arc with his right hand. ‘Looking at the topography, there are plenty of vantage points with ground cover — the shooter could have been anywhere within, I’d guess, around a mile radius.’
‘Can you get any clue from the way the body is lying?’ Grace asked.
Dyson shook his head. ‘It’s not critical whether the body or head are facing the same direction of the impact. In the case of instant death, which this looks like — from the catastrophic head injury — the body is likely to roll or fall in no particular pattern. The question we need to ask is whether this was a targeted head shot.’
‘Meaning what exactly?’ Grace asked.
‘Did the shooter hit at the head deliberately, or was he aiming for a body shot and the bullet went high? If we can work out what he was aiming at, we can estimate the maximum distance he would have been positioned from here.’
Grace frowned. ‘Can you explain how you can do that?’
Dyson nodded. ‘If we hypothesize the shooter was going for a head shot, and scored a bullseye, it gives us quite a lot of helpful information regarding the location of the shooter.’
‘Tell me?’
Dyson nodded and Grace could see the man’s expertise and passion shining in his expression. He walked closer to the tape and addressed both Grace and Downing. ‘We need to start with what accuracy we’d expect from the rifle we’re using, and how distance affects what’s capable. From the damage inflicted, I would guess one possible bullet might be a .338 Lap Mag with a ballistic tip, which has a velocity of 900 metres per second. This is supersonic. But at half a mile the bullet will have slowed to subsonic speeds. So from half a mile, say, we’d expect a bullet travel time of around 1.5 seconds. Then we have to factor in the amount of bullet drop — the bullet flies in a parabolic curve. The .338 has an average bullet drop, at half a mile, of around 152 centimetres. At 250 yards it drops to around 22 centimetres. This leads to issues when trying to hit a target the size of a human head at long range. We also have to factor in wind drift, the angle of the shot — downwards or upwards — as this affects the impact point. We’d also have to factor in that a human is a moving target. He might move in that one and a half seconds.’
He paused and Grace nodded, trying to process this, and saw the ACC looking like he was doing the mental maths, also. The ballistics expert continued. ‘Now we also have to factor in the skill of the shooter. What calibre of marksman would have the skill level to accomplish a head kill at half a mile? With a .338 or any calibre and rifle combination, in my view the probability for an amateur would be a success level of one in fifty. A trained military sniper would improve those odds to one in ten. A skilled privateer with a long background at winning target-shooting trophies, with home-loaded ammunition and perfect conditions — which they are today — maybe one in five — being generous.’
In the far distance they heard the faint muffled blasts of the twin barrels of a shotgun. A plane, en route to or from Gatwick Airport, flew high overhead. ‘So how would our shooter improve his odds of a head shot kill to certainty, Baz?’
‘He’d have to shoot from a very maximum range of three hundred yards. At that distance even for only a moderately experienced shooter, your head shot kill ratio would be very high.’
‘Three hundred yards?’ Grace said, looking up at the hills.
‘That’s where I’d start,’ Dyson said. ‘Somewhere in that range with both ground cover and a clear line to the target. I’d look for any cover within that distance that could hide the shooter. Areas or paths of ingress and evacuation. You’d identify the area by indications of ground disturbance — such as a flattened patch where someone may have lain prone for an extended period of time. Depressions where someone may have knelt or had elbows in the ground, and also imprints of bipod legs.’
Dyson knelt, opened his case and removed a compact laser rangefinder. He held it up to his right eye and began, very slowly, to scan an arc of the elevated countryside to the south of them, in a clockwise direction. He stopped to make an adjustment and then remained motionless, studying an area of hilly shrubland. Then he moved on and stopped again, staring intently at another area. He repeated this four more times. ‘Interesting,’ he murmured.
‘Interesting?’ Grace quizzed.
Without lowering the rangefinder, Dyson now steadily moved it anticlockwise, pausing a couple of times, before settling on one specific target. He studied it again for some while before he lowered the device. ‘I think I’ve located where the shooter was most likely to have been.’ He pointed at a hillock largely covered in bushes. ‘If you look at about one o’clock. It’s the right distance, with good ground cover from a thicket of gorse bushes. You wouldn’t see the shooter from here but he’d have clear line of sight of us. He’d also be able to see the entrance to the tunnel from there.’
He handed Grace the rangefinder and the Detective Superintendent peered through it, taking a moment to adjust the focus. He saw the red dot of the laser and the changing digital readout, in yards, as he moved it around. At 297 yards he thought he could see the small area Dyson was referring to. He lowered the instrument. ‘That is a possibility,’ he agreed.
‘What I’ll do is head over there and see if I’m right about the vantage point — by looking back at the body — and see if there are any signs of someone having been there recently.’
‘I’ll come with you,’ Grace said.
‘Be my guest,’ Dyson replied.
As they strode away from the crime scene, ducking under the far side of the inner cordon tape, the ballistics expert added, ‘I’ve been thinking about the weapon. If your witness is correct about the motorbike and the description of the canvas bag containing what he described as looking like a broken-down fishing rod, there is a weapon that would fit with that description. A Blaser LRS2 — a German-made classic sniper rifle, firing a .300 Win Mag with a ballistic tip. It’s got a range of two thousand metres, but as I said, to be accurate enough for a head shot, the distance would need to be three hundred metres or less. The bullet has all the power to inflict the damage we can see, and the reason I’m thinking the Blaser LRS2 is that its takedown ability works well for covert transportation.’
‘Takedown ability?’ Grace quizzed. ‘I’m sorry, I’m not familiar with that term.’ Despite the time of year, he was feeling increasingly warm and sticky in his new white onesie and clumsy overshoes, as they climbed a steep hillock. They had changed into new protective clothing to avoid contamination issues. The ballistics expert was perspiring too, from the effort of the trek.
‘It means you can take the weapon apart, for ease of transport — and covert transportation. The advantage of the Blaser LRS2 is that the scope is attached to the barrel, so its accuracy is never compromised when the weapon is reassembled. It also has a magazine capacity of ten rounds, with a straight pull action making quick second shots while staying on target much easier than a conventional bolt-action weapon. There is possibly another advantage for the sniper, if I’m correct about the weapon, which is that it is not used by any UK law enforcement agency nor by our military — making it harder to trace. There are other weapons it could be that I’m not ruling out yet, a Sako TRG 42 or even possibly an L115A3 sniper rifle.’