Jane looked closer and could see the number 43, ST+ and DNH. She asked what the numbers and letters meant.

‘The 43 is the year of manufacture, which is 1943. I’m not sure what ST+ means, but DNH is where the bullet was manufactured. However, the firearms section at the lab will be able to tell us more.’

‘The cartridge is nearly forty years old – what sort of gun do you think it was fired from?’

‘I don’t know . . . Again, that’s a job for the lab to determine. I’ve seen older ammo and nine-mill is used in different makes of revolvers and semi-automatics.’

‘Will you be able to get fingerprints off the cartridge?’

He shook his head. ‘Unfortunately, no, when a gun is fired, the heat created has a destructive effect on any fingerprint evidence. Even unfired bullets are almost impossible to get a print off.’

‘What’s GSR?’ she asked, remembering Kingston referring to it.

‘Gunshot residue. A plume of gas and GSR particles is ejected from the barrel of a gun when it’s fired, and the residue gets deposited on the skin and clothing of the person who fired the gun. It can also be found on the clothing of the victim, but that depends on how close they were to the gun when it was fired.’

‘So, the suspect who fired the gun that left these casings will have GSR on them.’

‘Yes, on his clothes for sure, but if he washes his hands and body then it’s gone from his skin. Whenever we arrest any suspects for armed robbery, we always Sellotape their hands for GSR and the lab examines the tapings under a scanning electron microscope to look for GSR as evidence they have fired, handled or been near a gun.’

‘You know a lot about firearms and bullets,’ Jane said respectfully.

‘Enough to get me by, but the forensic scientists are the experts. If you fancy it, you can come to the lab with me when I submit the cartridge cases and other evidence for examination. I think you’d find the firearms section really interesting and informative.’

‘I’d like that, thank you.’

She was warming to Dabs. His helpful, polite manner reminded her of Paul Lawrence.

‘I’ve ordered a tow truck to remove the police car to the lab, then it can be examined for any bullets that may be lodged in it. We need to crack on and photograph the scene, then gather up the cartridge cases before it gets here.’

*