It took a few minutes to fully regain focus, to push thoughts of Ben to the back of her mind, before she felt ready to move on. What worried her most was that she could see so much of herself in Ben. She had thought – or was it hoped? – that her short and often irrational temper, and her occasional violent outbursts, were a result of the TBI. But was that just wishful thinking? Were sister and brother in fact both defective in the same way? Was there some problem in their DNA?

That was the idea that scared her more than anything.

As kids, as twins, they hadn’t just been siblings but rivals. Everything was a competition between them; whether consciously or not, they fought over who was the best, the fittest, the strongest, the cleverest, the kindest, whatever. Somehow Dani, a true tomboy back then, had invariably come out on top, much to her brother’s general disgruntlement.

Over the years that feeling of inferiority in Ben had gradually worn at their relationship, which had culminated in a period, immediately after their mother had died, where brother and sister fell out of touch completely.

But was all of that the reason Ben had flipped and done the horrendous things he had? Simple jealousy and pent-up anger from a lifetime of playing second fiddle to his sister? Did he consider himself a failure, even though he’d had a spouse and a family while Dani had been too career-focused to have ever settled down?

If that was Ben’s only trigger, then there must still have been something inside him to make him capable of the acts he committed, and to allow him to rationalise breaking societal rules so flippantly. Not every jealous sibling goes on a murderous rampage. So did Dani, deep down, share those same killer traits as Ben? And was it simply circumstance which had meant that thus far in her life those traits had been buried beneath the surface?

Trying to take her mind off those depressing and worrying thoughts, Dani checked her phone. She had a missed call and a voicemail. She listened to the message from McNair. Her boss had briefed DCI Fairclough from the Organised Crime team on the deaths of Natalya and Paul Reeve, given Reeve’s clear link with the drug world. For now the Homicide team still had the lead, but it could be that Fairclough would soon take over.

Was the explanation for Reeve’s and Natalya’s deaths really as simple as gangland violence? Perhaps it was, though Dani felt there was something bigger and more sinister at play. After all, Reeve was connected to the missing Grace Agnew too.

Either way, she wasn’t impressed that the investigation was slipping from her grasp.