Now blood even stains the tarmac where I live

Then I noticed the police car parked at the foot of the road, and the officers in stab-proof vests heading into Whittington Park, off Holloway Road.

With a jolt, I realised the children weren't playing. They were gathering to witness the aftermath of a horrific crime. Moments earlier, two boys, aged 15 and 16, had been stabbed, their seriously injured bodies found slumped in my local park and outside a pub a couple of streets away.

But, shocking though this crime was, a worse incident overshadowed it - the knife murder in broad daylight of a young man on Oxford Street the very next day.

Three other stabbings occurred on Monday, two in Peckham, another in Dalston. All this and London was still reeling from the seemingly unprovoked slaying of schoolboy Jimmy Mizen in a bakery on Saturday, attacked buying sausage rolls with his brother.

Throughout this whole bloody episode I've felt nothing but sorrow and sympathy - for the victims, their families, the mess that our city is in because of the upsurge of knife culture.

And then something happened that turned my blood cold. I read that Steven Bigby, the Oxford Street victim, had been charged with one of the most sickening attacks of recent months - the gang-rape of a 16-year-old girl at a house on the North Circular Road. After the attack, her rapists doused her in caustic soda in an attempt to destroy DNA evidence.

She was left fighting for her life with unimaginable injuries.

That Bigby was not just a victim of violent crime but also stood accused of being a perpetrator has caused my liberal empathy to evaporate. Astonishingly, he was on bail. Not only for his alleged part in this gruesome rape, but also for a stabbing in north London in 2006.

We'll never know the true extent of Bigby's involvement in the crimewave sweeping London. But while I used to think the majority of these attacks happened in the heat of the moment, the partial picture we can now see suggests a sick and vicious cycle operating in uncomfortably close proximity to our own lives. This week I've had to cycle around police tape on my way to and from work, aware that children's blood still stains the tarmac.

Volatile men with pockets full of knives and drugs lashing out at each other is terrible enough. But that rape in January was sustained, coldblooded and sadistic. No number of excuses about culture and deprivation can forgive it. A group of men set out to ruin a girl's life, then disfigured her into the bargain.

Even the death of a bad man is a terrible loss for someone. But the real tragedy here is that Steven Bigby will never now face justice for the crimes of which he was accused.