The first murder trial I worked on was a choking case. I had just started practicing as a criminal lawyer and was asked to research “petechia” bruises. I had no idea what they were. I was given a set of colour photos of the middle-aged woman who had been strangled to death. In the first picture I saw little red marks, dots, on the lower part of her neck. Another photo showed the bottom of her eyelids folded down and red bruising covering the lower whites of her eyes. My real legal education had begun.

I took myself to the University of Toronto Medical Library and for two days read every article I could find about choking, bruising, cut-off air passages, fine neck bones and how easily they could be broken, bulging eyes, sweating foreheads, tongues sticking out, skin gone pale, lost control of bowels. I flipped through pages and pages of British forensic textbooks, with seemingly endless black-and-white photos of men and women strangled to death in the most terrible ways.

Petechia bruising, it turned out, occurred when the air was cut off to the brain. This forced the heart to pump harder, in a desperate attempt to push life-giving oxygen to the body. The bruising doesn’t occur in every case, and when it does sometimes it’s very subtle. Often only found, as in our case, by pulling back the lower eyelid. The bottom line was bad news for the defence: petechia bruises were a sure sign that someone had been choked.

I put together a detailed research report, and our client, who up until then had been in denial, soon pled guilty to manslaughter.

That was 23 years ago, and the images of those terrified faces, deprived of their last breath, have stayed with me. Since then I’ve tried many murder trials, but never another case when someone was choked to death. Murders like this are rare. It’s estimated that 10 per cent of all homicides in the U.S. are caused by some form of strangulation. Perhaps that is why when former CBC radio host Jian Ghomeshi was recently arrested for allegedly committing a number of offences, it was the choking charge that seemed to garner the curiosity of many media commentators.

There are very few sections of the Criminal Code of Canada that enumerate a specific act of violence, short of murder. For example, we now only have Sexual Assault, which covers everything from an unwanted grope to rape. When it comes to physical violence there is Assault, which means almost any possible form of physical contact without injury and Assault Causing Bodily Harm, which unless there is a homicide, covers the rest.

Logically, choking could fit into that category. But instead, it sits alone as its own specific offence. Why? I think it’s because there’s something about the notion of being choked that hits all of us on a visceral level. We all have necks. These thin appendages that carry our heads around with us every day.

It is perhaps the part of our body that is most vulnerable when it comes to life and death. Think of how we refer to our necks in everyday language. “Sticking our necks out” for someone or “putting our necks on the line.” It’s dangerous if we drive at “breakneck” speed. When he are burdened we carry “millstones around our necks.” When we have a vicious fight we are “at each other’s throats.” Lawyers even talk about “cutthroat” defences, when an accused turns on a co-accused. And of course if we really want to hurt someone, we “go for the jugular.”

In my non-lawyer life I write crime novels. This means I’m constantly on the look out for ways to kill my fictional characters. Having used up my share of knives and guns in previous novels, for my last book, Stranglehold, I wanted a murder that was intimate and angry. In the first chapter the main character, Homicide Detective Ari Greene, finds a woman he knows in a cheap motel room out on Kingston Road in the east end of Toronto. He knows with one look how she’d been killed and what it meant. Here’s what goes through his mind:

Every cop knew it was hard to strangle someone to death. You had to look them right in the eye. If this was done by a hired killer, or if it was a random act, you’d expect her to have been stabbed or shot. Choking homicides were textbook murders motivated by jealousy or anger. Personal rage.

I wanted this murder to hit the reader hard. For reasons that I think run deep within us, I could conjure up nothing more horrifying, more chilling, than choking.

Robert Rotenberg is a criminal lawyer in Toronto at the firm of Rotenberg, Shidlowski, Jesin. He is also the bestselling author of four murder mysteries set in Toronto.