As the lift light shines that they’ve reached the first floor, Joe waits for the door to slide open and takes a deep breath. He’s been with Wandsworth CID for nearly five years and has been involved in hundreds of attacks on teenagers over that time, from drunken fights between mates gone wrong, to stabbings initiated by warring gangs. It’s all too easy to treat new victims as just one more, forget that they are all the centre of someone’s world, and most with mothers who still remember tucking them in at night. This kid they’re seeing now might be half a foot taller than him, and full of patter on the night they met, but he’s still got his whole life ahead of him, and last night someone tried to take that from him.

The pair of them walk up to the reception desk and wait to be noticed. It was Joe’s day off yesterday, so he only found out about Mark’s attack when he came on shift at eight o’clock this morning. He was reading the details in the handover book when his sergeant, DS Flackwell, had wandered over and offered to give him the lowdown personally – while also neatly dropping the case in Joe’s lap.

A member of the public had seen Mark Sullivan sparko through the shop unit window in the early hours on their way home from a Christmas party. Apparently inspired by the post about Beth Packard dabbling in heroism a couple of weeks earlier, they’d assumed a drug overdose and phoned the emergency services. By the time the paramedics arrived, the good Samaritan had wandered off and Mark was crawling around on the pavement. He was clearly under the influence, but there was also a deep red ligature mark around his neck. With a suspected spinal fracture, he was collared and blocked, and taken to A&E at St George’s, where he was treated overnight. His condition has been described as stable, but he’s currently unconscious in ICU.

It hadn’t taken the on-duty CID long to work out Joe’s connection with Mark – the initial arrest for drug offences, and the allegation made by Mr Packard against him – or for them to flag to DS Flackwell that Joe might just be the man for the job. Luckily, it seems they were also out of the blocks quickly with the initial investigation. The on-call forensics officer has already been to the hospital, and shared photographs of Mark’s wounds. And a SOCO team are heading to the crime scene this morning.

‘Can I help you?’

‘DC Stone, Wandsworth CID,’ Joe says, showing his badge to the nurse who’s appeared behind the reception desk. ‘And this is DC Worthing.’